

Introduction We can remember about 10 years ago when 17" and 19" screens ruled the desktop monitor market. Something like the 24" Dell 2405FPW seemed a massive screen at the time and it was hard to imagine anything bigger on your desk. Flash forward to the end of 2014 and we have something rivalling many peoples TV's on our work-bench, a massive 40" display from Philips. The BDM4065UC is officially a desktop monitor in Philips' range, not only offering a huge screen size but also quad HD "4k" support. The 3840 x 2160 resolution is ideal for a screen this size for both desktop and multimedia use. The BDM4065UC comes with a pretty impressive spec and feature set and all at a very reasonable price. We will put it through its paces during this review. Commenting on the new 40-inch display with UltraClear 4K UHD resolution, Thomas Schade, Vice President EMEA at MMD says, “This new UltraClear UHD display is an exciting addition to the 4K line-up and sizes up the viewing experience at 4K level. With the clarity and brilliance of 4K UHD and 40 inches of screen real estate to play with, users will really notice the sense of space and precision detail in everything they do – from complex financial applications and scientific imaging to gaming or streaming movies.” If you appreciate the review and enjoy reading and like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you.

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Specifications and Features The following table gives detailed information about the specs of the screen: Monitor Specifications Size 39.56"WS (100.5 cm) Panel Coating Glossy coating Aspect Ratio 16:9 Interfaces D-sub, HDMI, DisplayPort, Mini DisplayPort, HDMI (with MHL), RS232 Resolution 3840 x 2160 Pixel Pitch 0.2281 mm Design colour Glossy black bezel, silver aluminium stand Response Time 8.5ms G2G

3ms G2G (Smart response) Ergonomics None Static Contrast Ratio 5000:1 Dynamic Contrast Ratio 50 million:1 VESA Compatible Yes 200mm Brightness 300 Accessories Power, USB, HDMI, DisplayPort, HDMI/MHL and VGA cables Viewing Angles 176 / 176 Panel Technology TP Vision VA-type Weight with stand: 9.7Kg Backlight Technology W-LED Physical Dimensions (WxHxD with stand)

904 x 589 x 213 mm Colour Depth 16.7m (8-bit) Refresh Rate 60Hz Special Features PiP (2 devices), PbP (4 devices), 2x 7W speakers, 4x USB 3.0 ports (inc 1 fast charging), audio input, headphone out. Uniformity correction, factory calibrated sRGB mode Colour Gamut Standard gamut

~sRGB, 72% NTSC The Philips BDM4065UC offers a good range of connectivity options with D-sub, HDMI, Mini DisplayPort, DisplayPort, MHL-HDMI and RS232 all provided. This should be enough for a wide variety of systems and external devices. Philips' "MultiView" function allows for multiple inputs to be shown on the screen at the same time, up to 4 simultaneously in fact. This is basically a Picture in Picture (PiP) or Picture By Picture (PbP) function, and because of the massive 3840 x 2160 resolution, you can actually have four 1920 x 1080 showing on the screen at the same time if you want! There's a wide range of configuration options detailed in the user manual for the MultiView settings. The screen has an integrated power supply and so it only needs a standard kettle lead which is provided in the box. There is a built-in 4 port USB 3.0 hub as well on this model, one with fast charging capability. The ports are the latest USB 3.0 generation which is good and located separately on the back of the screen. There are also a few other extras including integrated 2x 7W stereo speakers, an audio input connection and headphone jack. Below is a summary of the features and connections of the screen: Feature Yes / No Feature Yes / No Tilt adjust DVI Height adjust HDMI Swivel adjust D-sub Rotate adjust DisplayPort VESA compliant Component USB 2.0 Ports Composite USB 3.0 Ports Audio connection Card Reader HDCP Support Ambient Light Sensor MHL Support Human Motion Sensor Integrated Speakers Touch Screen PiP / PbP Hardware calibration Blur Reduction Mode Uniformity correction G-Sync



Design and Ergonomics

Above: front views of the screen. Click for larger versions The BDM4065UC has an attractive design, with subtle thin bezels and a minimalist stand. The bezel is a glossy black plastic measuring ~12mm around all sides of the screen. In the middle of the bottom bezel is a protruding black plastic section with a Philips logo and power LED on it. The LED glows white during screen operation. There are no other markings or model designations on the front of the screen at all.

Above: rear view of the screen. Click for larger version The back of the screen is a squared off matte black plastic which nicely encloses all the innards. There is a power socket on the left hand side (as viewed from behind as above). On the right you will notice the USB ports as well. The video connections are located on the right hand edge of the central back section which we will show you in a moment. There are VESA 200mm mounting holes provided on the back as well. The stand is packages separately and must be screwed onto the small metal arm provided, and slotted into the bottom of the screen where it is attached using the 4 provided screws.

Above: view of the stand. Click for larger version The base is a minimalist aluminium stand as shown above. It gives the screen a sturdy base and looks like a lot of current TV stands you will see.

Above: further views of the stand and base. Click for larger versions Above you can see the stand from some other angles, including on the right where it slots into the bottom of the screen on the back. The bottom edge of the screen is ~73mm from the edge of the desk.

Above: side view. Click for larger version The display has a fairly thin side profile so would be nice wall mounted. One main downside to this screen is the lack of any ergonomic adjustments at all. The screen sites up vertically as you would see from TV's. If you're sitting a couple of metres away for a game or movie this should be fine and what you want. However, if you're sitting a few feet away from a normal everyday desktop position, the lack of tilt is annoying. We ended up propping a small book underneath the front of the base to tilt it back slightly to write this review. There's no tilt, height, swivel or rotate adjustments at all from this screen so be wary. Mounting the screen on a monitor arm would give you more flexibility but obviously add to the overall cost. The stand is like most TV designs which is one thing, but this is supposed to be a desktop display so we would have liked more from the stand on this screen. A summary of the screens ergonomic adjustments is shown below: Function Range Smoothness Ease of Use Tilt None n/a n/a Height None n/a n/a Swivel None n/a n/a Rotate None n/a n/a Overall Lack of any ergonomic adjustments which is a shame The materials were of a good standard and the build quality felt good as well. There was no audible noise from the screen, even when conducting specific tests which can often identify buzzing issues. The whole screen remained reasonably cool even during prolonged use as well, with a bit of heat given off.

Above: interface connections on right hand side back of the screen

Above: USB interfaces back of the screen. Click for larger version The right hand side of the back central section features all the video connections as shown above. There are also the audio connections here, all pretty easy to get to and access if you need to. On the back of the screen are the 4 USB 3.0 ports (and 1x upstream) which are again easy to access.



OSD Menu

Above: views of OSD operational buttons on the bottom right hand edge of the screen The OSD menu is controlled through a single joystick controller which is located on the back right hand corner of the screen (as viewed from the front). This controls all aspects of the OSD and does take a bit of getting used to. The menu software is pretty big and looks low-res on such a nice high res screen. It serves its purpose though. The joystick gives you quick access to a few options. Pressing it left brings up the SmartImage preset mode menu as shown above. Pressing the joystick up brings up the MultiView menu, and down brings up the audio source menu. Pressing the joystick right brings up the main OSD menu as shown above. It's split in to 8 sections shown down the left hand side, with the relevant options for each section shown on the right hand side. You have to press the joystick left to go back/exit a menu. Pressing the joystick in like a button actually doesn't do anything, contrary to what you might expect. Once you're in a menu it's a bit tricky at first to figure out what does what. Sometimes you need to press right to go into a section, then when you're in the option (like brightness for instance) it brings up a separate control for the brightness setting, at which point rather than using left and right to slide the setting left and right as you would expect, you revert to using up/down to change it. It can be a bit confusing sometimes and isn't very intuitive. The picture menu contains most of the useful settings. You can control the hardware aspect ratio here, brightness, contrast etc. Also there's the control over the response time, dynamic contrast ratio and gamma preset. The pixel orbiting function is a measure designed to reduce the chances of image burn in. The screen actually gives you warning messages as well about burn in. Pixel orbiting is usually used on plasma backlit screens, but it's been included here on this LED backlit model. Maybe it's a panel which is prone to issues with image retention, maybe Philips are just being cautious. Best to leave that turned on, and also set a monitor turn off timer in your Operating system after a period of inactivity. If nothing else that will help with your energy saving. The PiP/PbP menu controls all the MultiView settings if you are using multiple inputs. The audio menu controls the speakers and the audio source. The color menu has a couple of useful options. You can choose from a series of preset colour temp modes here, or enter the factory calibrated sRGB mode, or a user define mode where you can alter the RGB levels yourself. More on that later in the review. The other sections shown above are pretty self explanatory. Important 4k Note: One thing to note is that the screen comes as default set at DisplayPort mode 1.1. This will only support 3840 x 2160 at 30Hz maximum, so if your graphics card supports DP 1.2 you need to go into this section and change the setting to 1.2. This will then allow you to set the screen at the full 60Hz refresh rate in Windows. The screen is detected as a single display (Single Stream Transport, SST) as opposed to MST for those interested. There is a hidden factory menu which can be accessed by holding the joystick away from the power button (right if seen from the front, left if seen from the rear), as you turn on the screen. Once on, go into the normal OSD and there's a new section at the bottom. Changes are not advised and are entirely at your own risk.



Power Consumption In terms of power consumption the manufacturer lists 77.6W typical usage, 140W maximum usage and <0.5W in standby. We carried out our normal tests to establish its power consumption ourselves. State and Brightness Setting Manufacturer Spec (W) Measured Power Usage (W) Factory Default (100%) 77.6 81.0 Calibrated (34%) - 49.0 Maximum Brightness (100%) 140.0 81.0 Minimum Brightness (0%) - 35.1 Standby <0.5 0.8 We tested this ourselves and found that out of the box the screen used 81.0W at the default 100% brightness setting. Maximum usage specified would presumably be with USB connected etc as well. Once calibrated the screen reached 49.0 W consumption, and in standby it used only 0.8W. We have plotted these results below compared with other screens we have tested:



Panel and Backlighting Panel Manufacturer TP Vision Colour Palette 16.7 million Panel Technology VA (Vertical Alignment) Colour Depth 8-bit Panel Module TPT400LA-K1SQ1.N Rev:SC1A Colour space Standard Gamut Backlighting Type W-LED Colour space coverage (%) ~sRGB, 72% NTSC Panel Part and Colour Depth The Philips BDM4065UC utilises an unusual panel from a manufacturer we've not seen before. The panel is made by TP Vision, who are affiliated with TPV Technology and Philips. So effectively it's a Philips-own panel used here. It is Vertical Alignment (VA) technology and the panel part is the TPT400LA-K1QS1.N Rev: SC1A. The panel is capable of producing 16.7 million colours. This is achieved with an 8-bit colour depth. The panel is confirmed when dismantling the screen as shown below, as well as within the OSD factory menu:

Screen Coating The screen coating on BDM4065UC is a glossy solution. It has moderate levels of reflection very similar to a lot of modern LCD TV's really. It's not overly reflective like some glass fronted desktop displays we've seen in the past (Dell S2440L / S2740L for instance) so it's pretty easy to work with. Being glossy it does provide a nice clear and crisp image and it helps make colours and blacks pop somewhat.

Backlight Type and Colour Gamut The screen uses a White-LED (W-LED) backlight unit which has become very popular in today's market. This helps reduce power consumption compared with older CCFL backlight units and brings about some environmental benefits as well. The W-LED unit offers a standard colour gamut which is approximately equal to the sRGB colour space, and equating to ~72% NTSC. Anyone wanting to work with wider colour spaces would need to consider wide gamut backlit displays instead.

Backlight Dimming and Flicker We tested the screen to establish the methods used to control backlight dimming. Our in depth article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). This in itself gives cause for concern to some users who have experienced eye strain, headaches and other symptoms as a result of the flickering backlight caused by this technology. We use a photosensor + oscilloscope system to measure backlight dimming control with a high level of accuracy and ease. These tests allow us to establish 1) Whether PWM is being used to control the backlight

2) The frequency and other characteristics at which this operates, if it is used

3) Whether a flicker may be introduced or potentially noticeable at certain settings If PWM is used for backlight dimming, the higher the frequency, the less likely you are to see artefacts and flicker. The duty cycle (the time for which the backlight is on) is also important and the shorter the duty cycle, the more potential there is that you may see flicker. The other factor which can influence flicker is the amplitude of the PWM, measuring the difference in brightness output between the 'on' and 'off' states. Please remember that not every user would notice a flicker from a backlight using PWM, but it is something to be wary of. It is also a hard thing to quantify as it is very subjective when talking about whether a user may or may not experience the side effects.

100% 50% 0%



Above: scale = 1ms per horizontal grid

Above: scale = 10ms per horizontal grid At 100% brightness a constant voltage is applied to the backlight as you would expect. As you reduce the brightness setting a Pulse Width Modulation technique is used for backlight dimming. This operates at a low and fixed 240Hz throughout the brightness adjustment range, and the duty cycle (on time) is just reduced as you lower the brightness setting. This low frequency PWM dimming could present some problems to those with sensitive eyes or those prone to issues with flicker. Pulse Width Modulation Used Yes Cycling Frequency 240Hz Possible Flicker at 100% Brightness No 50% Brightness Yes 0% Brightness Yes For an up to date list of all flicker-free (PWM free) monitors please see our Flicker Free Monitor Database.

Contrast Stability and Brightness We wanted to see how much variance there was in the screens contrast as we adjusted the monitor setting for brightness. In theory, brightness and contrast are two independent parameters, and good contrast is a requirement regardless of the brightness adjustment. Unfortunately, such is not always the case in practice. We recorded the screens luminance and black depth at various OSD brightness settings, and calculated the contrast ratio from there. Graphics card settings were left at default with no ICC profile or calibration active. Tests were made using an X-rite i1 Display Pro colorimeter. It should be noted that we used the BasICColor calibration software here to record these, and so luminance at default settings may vary a little from the LaCie Blue Eye Pro report. OSD Brightness Luminance

(cd/m2) Black Point (cd/m2) Contrast Ratio

( x:1) 100 280.21 0.05 5604 90 256.07 0.05 5121 80 230.60 0.05 4612 70 205.60 0.04 5140 60 179.10 0.04 4478 50 150.77 0.03 5026 40 128.77 0.03 4292 30 106.67 0.02 5334 20 81.66 <0.02 - 10 57.95 <0.02 - 0 32.37 <0.02 - Total Luminance Adjustment Range (cd/m2) 247.84 Brightness OSD setting controls backlight? Total Black Point Adjustment Range (cd/m2) >0.03 Average Static Contrast Ratio 4951:1 PWM Free? Recommended OSD setting for 120 cd/m2 36 Tests were carried out at default screen settings. The brightness control gave us a very good range of adjustment. At the top end the maximum luminance reached 280.21 cd/m2 which was only just shy of the specified maximum brightness of 300 cd/m2 by the manufacturer. There was a 247.84 cd/m2 adjustment range in total, and so at the minimum setting you could reach down to a nice low luminance of 32.37 cd/m2. This should be more than adequate for those wanting to work in darkened room conditions with low ambient light. A setting of ~36 in the OSD menu should return you a luminance of around 120 cd/m2 at default settings. We have plotted the luminance trend on the graph above. The screen behaves as it should in this regard, with a reduction in the luminance output of the screen controlled by the reduction in the OSD brightness setting. This was pretty much a linear relationship as you can see from the shape of the graph. It should be noted that the brightness regulation is controlled using Pulse Width Modulation at all brightness settings below 100, and at a low frequency of 240Hz. This could be problematic to those prone to eye fatigue or headaches associated with flickering backlights. Not everyone is affected of course, but we advise caution. The average contrast ratio of the screen was an amazing 4951:1. We have not included the contrast stability graph as rounding errors lead to discrepancies with such a low black point measurement. Below a setting of ~25 brightness the black depth becomes too low to be measured by our i1 Display Pro device, which is why we've listed it as <0.02 in the table for settings below 30.



Testing Methodology An important thing to consider for most users is how a screen will perform out of the box and with some basic manual adjustments. Since most users won't have access to hardware colorimeter tools, it is important to understand how the screen is going to perform in terms of colour accuracy for the average user. I restored my graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using an X-rite i1 Pro Spectrophotometer (not to be confused with the i1 Display Pro colorimeter) combined with LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro colorimeter was also used to verify the black point and contrast ratio since the i1 Pro spectrophotometer is less reliable at the darker end.

Targets for these tests are as follows: CIE Diagram - validates the colour space covered by the monitors backlighting in a 2D view, with the black triangle representing the displays gamut, and other reference colour spaces shown for comparison

Gamma - we aim for 2.2 which is the default for computer monitors

Colour temperature / white point - we aim for 6500k which is the temperature of daylight

Luminance - we aim for 120 cd/m 2 , which is the recommended luminance for LCD monitors in normal lighting conditions

Black depth - we aim for as low as possible to maximise shadow detail and to offer us the best contrast ratio

Contrast ratio - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

dE average / maximum - as low as possible. If DeltaE >3, the color displayed is significantly different from the theoretical one, meaning that the difference will be perceptible to the viewer. If DeltaE <2, LaCie considers the calibration a success; there remains a slight difference, but it is barely undetectable. If DeltaE < 1, the color fidelity is excellent.



Default Performance and Setup Default settings of the screen were as follows: Monitor OSD Option Default Settings Brightness 100 Contrast 50 Smart Image preset mode Off Color Temperature 6500k Gamma 2.2

Philips BDM4065UC - Default Factory Settings







Default Settings luminance (cd/m2) 298 Black Point (cd/m2) 0.05 Contrast Ratio 5604:1 Out of the box the screen looked reasonable to the naked eye. Colours felt even and well balanced if perhaps slightly too blue. The brightness was too high as the brightness setting was maxed out at 100. We went ahead and measured the default state with the i1 Pro. The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) matches the sRGB colour space very well, with some minor over-coverage in blue shades being evident. Default gamma was recorded at 2.2 average, leaving it with a very minor 2% deviance from the target of 2.2 which was pleasing. White point was measured at 7077k leaving it a moderate 9% out from our target of 6500k and being a little too cool. Luminance was recorded at a very bright 298 cd/m2 which is too high for prolonged general use. The screen was set at a default 100% brightness but that is easy to change of course to reach a more comfortable setting without impacting other aspects of the setup. The black depth was an incredibly low 0.05 cd/m2 at this default brightness setting, giving us an amazing static contrast ratio of 5604:1. Colour accuracy was reasonable out of the box with a default dE of 2.4, but a maximum of 8.7 in blue shades. Testing the screen with various gradients showed smooth transitions with no sign of any banding thankfully. There was some very slight gradation evident in darker tones as you will see from most monitors. Overall the default setup was pretty decent and we were impressed certainly by the very high contrast ratio from the VA panel. Monitor OSD Option Default Settings

User define mode Brightness 100 Contrast 50 Smart Image preset mode Off Color Temperature User Define Gamma 2.2 RGB 100, 100, 100

Philips BDM4065UC - Default Settings, User Define mode



Default Settings

User define mode luminance (cd/m2) 308 Black Point (cd/m2) 0.05 Contrast Ratio 5840:1 We also tested the default 'user define' mode. In the user define mode you are able to change the RGB levels manually if you want which we will use in the following calibration section. By default they are all set at 100 each. In this mode you will note the slightly higher static contrast ratio and brightness, since the RGB levels are all maxed out. Unfortunately by default the colour temperature in this mode is way off, being very cool visually and measured by our i1 Pro at 9539k (47% deviance). If we are to use this mode we will need to adjust the RGB channels to get a more accurate white point closer to the desired 6500k and bring the blue gain down significantly. Update Note 18 March 2016 We've had a few readers contact us in recent months about an issue some people have experienced with the screen where colours appear to "bleed" in to other areas of the screen. The above Youtube video gives a good demonstration of the issue reported. We didn't experience this on our test unit when we reviewed it back in 2014, although we weren't specifically looking for it so it's hard to say 100% whether the unit was affected or not. We certainly didn't notice these kind of problems on that sample in day to day normal uses and throughout the course of our testing. If you do buy this screen and find you are affected in your uses, we would recommend returning it or attempting a replacement with Philips. We are referencing this issue here for completeness more than anything.

Factory Calibration Monitor OSD Option Default Settings

sRGB mode Brightness 100 Contrast 50 Smart Image preset mode Off Color Temperature sRGB Gamma 2.2

Philips BDM4065UC - Default Settings, sRGB mode



Default Settings,

sRGB mode luminance (cd/m2) 297 Black Point (cd/m2) 0.05 Contrast Ratio 5622:1 We also wanted to test the factory calibrated sRGB mode which is available within the 'color' section of the OSD menu. When you enable this mode, the brightness setting is actually locked at 100. If you try and change the setting it tells you it is going to revert back to the 6500k mode as before. That's a shame as you can see the sRGB mode actually offered a more reliable default setup. Being bound to a maximum brightness though makes it rather pointless and not something you can comfortably use day to day. This mode offered a white point closer to the 6500k target, being measured at 6779k with a 4% deviance. Colour accuracy was also a bit better with less deviance in the blue shades now. This would have been a useful mode for colour work if you'd been able to adjust the brightness setting in the OSD menu.

Calibration We used the X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An X-rite i1 Display Pro colorimeter was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device. Monitor OSD Option Calibrated Settings Brightness 34 Contrast 50 Smart Image preset mode Off Color Temperature User Define Gamma 2.2 RGB 100, 99, 84

Philips BDM4065UC - Calibrated Settings



Calibrated Settings luminance (cd/m2) 120 Black Point (cd/m2) 0.03 Contrast Ratio 4128:1 We stuck with the 'user define' color mode in the OSD menu which allowed us access to the individual RGB channels. Adjustments were made during the process to the RGB channels as shown in the table above as well as the brightness control. This allowed us to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level. We left the LaCie software to calibrate to "max" brightness which would just retain the luminance of whatever brightness we'd set the screen to, and would not in any way try and alter the luminance at the graphics card level, which can reduce contrast ratio. These adjustments before profiling the screen would help preserve tonal values and limit banding issues. After this we let the software carry out the LUT adjustments and create an ICC profile. Average gamma had been corrected spot on to 2.2 average, correcting the minor 2% deviance we'd found out of the box which was good. The white point was also corrected to 6487k, correcting the moderate 9% deviance we'd seen before as well in the 6500k default mode. You will note that we have massively reduced the blue channel here to make the image warmer than the default user define mode which was far too cool. Luminance had also been improved thanks to the adjustment to the brightness control and was now being measured at 120 cd/m2. This left us a black depth of 0.03 cd/m2 and an excellent static contrast ratio of 4128:1. This was lower than the out of the box settings since we had adjusted the RGB channels now, and also corrected the white point through the graphics card profiling. It was still an excellent static contrast ratio though. Colour accuracy had been corrected nicely also, with dE average of 0.7 and maximum of 1.3. LaCie would consider colour fidelity to be excellent. Testing the screen with various colour gradients showed smooth transitions. There was some very slight gradation in darker tones but no banding was introduced which can often happen where adjustments are made to the graphics card LUT from the profilation of the screen. You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another. Calibration Performance Comparisons

The comparisons made in this section try to give you a better view of how each screen performs, particularly out of the box which is what is going to matter to most consumers. When comparing the default factory settings for each monitor it is important to take into account several measurement areas - gamma, white point and colour accuracy. There's no point having a low dE colour accuracy figure if the gamma curve is way off for instance. A good factory calibration requires all 3 to be well set up. We have deliberately not included luminance in this comparison since this is normally far too high by default on every screen. However, that is very easily controlled through the brightness setting (on most screens) and should not impact the other areas being measured anyway. It is easy enough to obtain a suitable luminance for your working conditions and individual preferences, but a reliable factory setup in gamma, white point and colour accuracy is important and not as easy to change accurately without a calibration tool. From these comparisons we can also compare the calibrated colour accuracy, black depth and contrast ratio. After a calibration the gamma, white point and luminance should all be at their desired targets. Default setup of the screen was pretty decent overall. Gamma was accurate, colour accuracy dE was nice and low and we had an amazing contrast ratio thanks to the VA panel. The white point let it down a little as it was 9% out from the target and a bit too cool. Easy enough to adjust and correct through calibration though which was good news. The panel did extremely well in terms of black depth and contrast ratio, with a calibrated contrast ratio of 4128:1 measured. In the past we've seen common AMVA contrast ratios of around 2000 - 3000:1 from panels manufactured by AU Optronics. The Eizo FG2421 had reached 4845:1 with its Sharp MVA panel. Here, the TP Vision VA panel of the Philips BDM4065UC reached up to 4128:1 after calibration. Contrast ratio was an obvious strong point of this panel, far out-doing anything which TN Film or IPS-type panels can offer (up to around 1000:1 in best cases).

Viewing Angles

Above: Viewing angles shown from front and side, and from above and below. Click for larger image Viewing angles of the BDM4065UC were quite comparable to other VA panels we've seen in the past. Horizontally the viewing angles were not bad. As you moved you line of sight past about 45° contrast shifted and a pale tint appeared on the image. The image got progressively more washed out as you moved further away from a central point of view. On some older AMVA panels the image tends to go very yellow from a wide horizontal angle but on the BDM4065UC it just went pale and washed out instead. Vertically the contrast shift was more pronounced and the image became more washed out from a shorter angle. This was actually apparent slightly when using the screen from a couple of feet away on a normal desktop position. Being pretty tall, my line of sight was about 3/4 of the way up the screen if I looked head on. If I glance towards the bottom of the screen the image becomes slightly washed out due to the viewing angles. If you move further back from the screen for movies or games, you don't see this, it's only when up close and due to the sheer size of the screen. Viewing angles were not as wide as IPS or PLS panels as you might expect given this is a VA matrix. They were not too bad though compared with a lot of other VA panels out there which was pleasing. The contrast shifts were evident here from wider angles, but there was very little colour tone shift thankfully which is far more noticeable on most other VA panels. Being VA based the panel did suffer from the off-centre contrast shift you will see from these technology panels. If you view a very dark grey image with a black background head on, the grey content is somewhat lost in the image and appears darker than intended. Only as you move your line of sight slightly away from a head on central field of view does the grey content appear again. This is common of all VA matrices, and is one of the reasons why IPS is so popular for colour critical work. It should be noted that not everyone would even see this issue or be bothered by it. The viewing angles are certainly much better than TN Film panels of course.

Above: View of an all black screen from the side. Click for larger version On a black image there was a slight pale glow from an angle but it was nothing really bad at all. Certainly you don't get the obvious white glow you see on a lot of IPS and PLS panels when viewing dark content from an angle. From that point of view this is one area where VA panel viewing angles are preferred.

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Panel Uniformity We wanted to test here how uniform the brightness was across the screen, as well as identify any leakage from the backlight in dark lighting conditions. Measurements of the luminance were taken at 35 points across the panel on a pure white background. The measurements were taken using BasICColor's calibration software package, combined with an X-rite i1 Display Pro colorimeter with a central point on the screen calibrated to 120 cd/m2. The below uniformity diagram shows the difference, as a percentage, between the measurement recorded at each point on the screen, as compared with the central reference point. It is worth noting that panel uniformity can vary from one screen to another, and can depend on manufacturing lines, screen transport and other local factors. This is only a guide of the uniformity of the sample screen we have for review.



Uniformity of Luminance

The luminance uniformity of the screen was moderate overall although there were clearly some areas which were much darker than the rest. The 4 corners seemed to be the problem, where luminance dropped down by a maximum of ~35% to 89 cd/m2 in the most extreme example. The central zones of the screen were more uniform and around 48% of the screen was within a 10% deviance from the centrally calibrated 120 cd/m2 point. This wasn't great unfortunately. Not likely to be an issue for gaming and movies, but perhaps problematic if you were wanting to do any colour critical work with large colour patches.

Uniformity of Luminance

Smart Uniformity = On

The BDM4065UC also features a uniformity correction mode which according to the spec should offer uniformity of 96 - 105%. This is accessed through the preset mode menu using the "SmartUniformity" option. As you can see, some of the uniformity issues have been improved now. The upper corner regions of the screen were a bit brighter than the central zone, ranging up by 11% in the most extreme cases which wasn't bad really. Around 97% of the screen was now within a 10% deviance from the centrally calibrated point which was far better and actually a very good result. This uniformity correction feature seemed to work very nicely and we imagine users might want to use this, certainly for any colour critical work they might be doing. This does beg the question though as to whether this mode has an impact on other aspects of the image. We went back to measure the setup in this mode: Monitor OSD Option Default Settings

SmartUniformity mode Brightness 100 Contrast 50 Smart Image preset mode SmartUniformity Color Temperature 6500k Gamma 2.2

Philips BDM4065UC - Default Settings, SmartUniformity mode



Default Settings

SmartUniformity mode luminance (cd/m2) 198 Black Point (cd/m2) 0.05 Contrast Ratio 3851:1 You can use each of the different color modes still while in this new preset mode, and the screen defaults back to the defined 6500k colour temperature mode first of all. You can use the 'user define' mode still and adjust the RGB channels yourself which we will look at in a moment. Unfortunately while the SmartUniformity mode offers an improvement to the uniformity of the screen, some other areas are impacted negatively. At 100 brightness, we are now limited to a maximum luminance of 198 cd/m2. Not actually a bad thing as the maximum before was ~ 300 cd/m2. We did have a reduced contrast ratio though, down from 5604:1 when the setting was off (everything else the same as it is here), to 3951:1 now. Still a very high contrast ratio of course. Gamma had unfortunately now strayed away from our 2.2 target, with an average of 2.0 measured leaving an 11% deviance. White point was also cooler even than before, with a 7662k white point measured, leaving an 18% deviance. Colour accuracy was close to the default 6500k mode when SmartUniformity was off, with dE average pf 2.8 and maximum of 6.0. The gamma and white point deviance was the main sacrifices made when switching to this uniformity correction mode we felt and you will need to do some calibration to correct those. Monitor OSD Option Calibrated Settings

SmartUniformity mode Brightness 58 Contrast 50 Smart Image preset mode SmartUniformity Color Temperature User Define Gamma 2.2 RGB 100, 99, 78

Philips BDM4065UC - Calibrated Settings, SmartUniformity mode



Calibrated Settings

SmartUniformity mode luminance (cd/m2) 119 Black Point (cd/m2) 0.03 Contrast Ratio 3933:1 We went ahead and calibrated the screen again, this time with SmartUniformity turned on. We reverted back to the 'user define' color mode to give us control over the RGB channels, and we again had to bring the blue gain down a lot to compensate for the cool default setting. If nothing else, the changes to the OSD settings should get you to a more accurate white point, but profilation using a calibration tool will be necessary to correct the gamma curve and make some more advanced adjustments. After calibration we had reached the gamma and white point targets nicely. You will need to have brightness set ~58 to achieve the desired luminance when you have SmartUniformity enabled. Colour accuracy had been corrected pretty nicely, although there did seem to be some deviance in reds where dE reached up to 2.8. This didn't seem to be possible to correct fully. The SmartUniformity mode did offer improvements to the screens uniformity so we would recommend switching to that mode certainly for any colour critical work. That is on the assumption that you have a calibration device or some way to correct the resulting gamma and white point though, as these are further out from the targets than when you have SmartUniformity off. You can of course use our calibrated settings and try our ICC profile which might help improve things for you anyway.

Backlight Leakage



Above: All black screen in a darkened room. Click for larger version As usual we also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. Three was no noticeable backlight bleed or clouding at all, and the screen offered very deep and dark blacks thanks to its VA panel.

General and Office Applications The BDM4065UC is a very interesting option for desktop use. The quad HD 3840 x 2160 resolution is well suited to a screen as big as this and offers a comfortable pixel pitch and font size by default, without the need to do OS scaling. We had previously found the text size and pixel pitch a little too small when we tested the 31.5" sized Dell UP3214Q and certainly very tiny when we tested the 28" sized Samsung U28D590D. You can of course use various scaling methods to make 4k resolutions more usable on smaller screens, but it's not always easy to get something set up for all your uses. While some Operating systems scale well, others do not, and a lot of apps also have problems with the scaling. Here on the BDM4065UC you don't need to bother with scaling at all, you can just run the screen and operating system at it's normal settings without the text being too small. The pixel pitch of 0.2281 mm is very comparable to the 0.2331 mm of a 27" 2560 x 1440 resolution panel. This is perfectly fine for day to day use. With the high resolution and huge screen size you have plenty of room for multi-tasking and split screen working which is great news. For word processing, CAD/CAM, image editing, programming etc it's really a massive area to use. You do need to keep in mind the need for a compatible graphics card with a suitable output which can handle this resolution, and preferably at 60Hz refresh rate. DisplayPort is the only option to run the screen at its native 3840 x 2160 res at 60Hz, so is certainly recommended. When running at native resolution this model is recognised as a single display which makes life easier than some of the early MultiStream (MST) 4k models. It's also good to see support for 60Hz refresh rate as some 4k models only offer 30Hz support which is very limiting, even in day to day uses (certainly for gaming!). The glossy AG coating of the panel provides clear and crisp images. It is not overly reflective like some glass-fronted screens for instance, but there's no graininess of any kind from an AG coating here. The reasonably wide viewing angles provided by the VA panel technology helps minimize on-screen colour shift when viewed from different angles. The vertical angles are somewhat restrictive though and you can notice some colour washout vertically when using the screen up close. The default setup of the screen was pretty good in most areas, with only brightness needing to be turned down to something more comfortable (which doesn't affect other aspects of the setup) and some minor correction to the white point needed. The contrast ratio was excellent thanks to the VA panel, and certainly a major strong point of this panel. The SmartUniformity mode improved the uniformity of the panel nicely, but the default setup of this mode needs some further tweaking to get to a more reliable setup. The factory calibrated sRGB mode offered a very good setup, but with brightness locked at 100% in that mode it renders it unusable. The brightness range of the screen was very good, with the ability to offer a luminance between 280 and 32 cd/m2. This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms. A setting of ~36 in the OSD brightness control should return you a luminance close to 120 cd/m2 out of the box. On a less positive note, the brightness regulation is controlled using the now infamous Pulse-Width Modulation (PWM), for all settings below 100 unfortunately. This operates at a low 240Hz frequency as well so could present problems to some users who are affected by flickering backlights. There was no audible noise or buzzing from the screen, even when specifically looking for it using test images with a large amount of text at once. The screen also remains pretty cool even during prolonged use. There are no specific paper/reading type preset modes available from the OSD menu on this model. The screen offers 4x USB 3.0 ports which can be useful and it was nice to keep this up to date with the modern version. There are also some further extras including one of those ports supporting fast-charge, audio input/output connections, integrated 2x 7W stereo speakers and a whole range of PiP and PbP options. One major drawback of the screen is the lack of any ergonomic adjustments from the stand, not even tilt. We felt the screen was too upright for close proximity office working so you will either need to prop something under the front of the stand to tilt it back a bit, or wall/arm mount the screen via the VESA 200mm holes.

Above: photo of text at 3840 x 2160 (top) and 1920 x 1080 (bottom) The screen is designed to run at its native resolution of 3840 x 2160 and at a 60Hz recommended refresh rate. However, if you want you are able to run the screen outside of this resolution. We tested the screen at a lower 1920 x 1080 resolution to see how the screen handles the interpolation of the resolution, while maintaining the same aspect ratio of 16:9. At native resolution the text was sharp as you can see from the top photograph. There did appear to be some slight overlapping of pixels but you couldn't spot this during normal use. When you switch to a lower resolution the text is larger of course but still pretty clear, with low levels of blurring introduced. The screen seems to interpolate the image quite well although you of course lose a lot of desktop real-estate running at a lower resolution. This is at least positive news for if you want to game or watch content from an external device at 1080p.



Responsiveness and Gaming Quoted G2G Response Time 8.5ms G2G

3ms G2G (SmartResponse ) Quoted ISO Response Time n/a Panel Manufacturer and Technology TP Vision VA Panel Part TPT400LA-K1QS1.N Rev: SC1A Overdrive Used Yes Overdrive Control Available to User 'SmartResponse' Overdrive Settings Off, Fast, Faster, Fastest The BDM4065UC is rated by Philips as having an 8.5ms G2G response time and the panel uses overdrive / response time compensation (RTC) technology to boost pixel transitions across grey to grey changes. They also list an adventurous 3ms G2G figure for when using the 'SmartResponse' setting, which is basically an overdrive control. There are options for this overdrive setting for off, fast, faster and fastest. The part being used is the TP Vision TPT400LA-K1QS1.N Rev: SC1A panel. Have a read about response time in our specs section if you need additional information about this measurement. We will first test the screen using our thorough response time testing method. This uses an oscilloscope and photosensor to measure the pixel response times across a series of 20 different transitions, in the full range from 0 (black) to 255 (white). This will give us a realistic view of how the monitor performs in real life, as opposed to being reliant only on a manufacturers spec. We can work out the response times for changing between many different shades, calculate the maximum, minimum and average grey to grey (G2G) response times, and provide an evaluation of any overshoot present on the monitor. We use an ETC M526 oscilloscope for these measurements along with a custom photosensor device. Have a read of our response time measurement article for a full explanation of the testing methodology and reported data. Response Time Setting Comparison (SmartResponse option) The BDM4065UC comes with a user control for the overdrive impulse available within the OSD menu in the picture section of the menu as shown above. There are four options under the 'SmartResponse' setting. First of all we carried out a smaller sample set of measurements in all three of the settings. These, along with various motion tests allowed us to quickly identify which was the optimum setting for this screen. With the setting turned off, the pixel transitions were actually good for a VA panel and we were impressed. There was an average 8.0ms G2G response time measured here which was pleasing. There was one transition measured which seemed to be problematic, the change from black to white (0-255) where there was a stepping in the brightness curve and it took a while to reach the desired luminance. The rest of the transitions were faster and averaged ~7.1ms G2G. There was no overshoot with the overdrive control set to off which was pleasing. Pushing the overdrive setting up to 'Fast' brought about some changes. Response times were a bit better now with an average of 6.4ms G2G measured. The 0-255 transition was still a problem, as that transition already had the maximum voltage applied to it anyway (since it's the most extreme change in pixel orientation), and so there was nothing more that the overdrive impulse could do. While additional voltages were being applied to overdrive the other transitions, this was still stuck with a slow response time. If we ignored this slow transition the response times would be more like ~5.3ms G2G. Unfortunately even with this first overdrive setting (Fast) there was some significant and noticeable overshoot introduced. This was at a high level and so this mode should probably be avoided. You can spot nasty trailing in moving images and it's a shame this first overdrive setting wasn't a bit more modest. We would expect aggressive overshoot from the higher overdrive settings, but not from this first step! With overdrive pushed up to the 'Faster' setting there was another reduction in response times, down to 5.5ms G2G average. Overshoot was now horrendous though and certainly even more noticeable in practice. The 'Fastest' mode pushed things even further, and the overshoot was massive. This should certainly be avoided.

Transition: 0-255-0 (scale = 20ms), SmartResponse = Off

Transition: 0-255-0 (scale = 20ms), SmartResponse = Fastest To show that the 0-255 transition was always slow no matter which overdrive setting you use, you can compare the graphs for SmartResponse 'off' and 'Fastest' above. The stepping of the brightness curve resulted in a slow rise time on this transition. If we also carry out some subjective assessment of the screen during gaming and with the use of the PixPerAn moving car tests, we can also see the differences between each overdrive mode easily enough with the naked eye. With SmartResponse (overdrive) off there was low levels of blurring to the moving image and no sign of any overshoot. As you push the overdrive control up to fast, a noticeable dark overshoot is evident. This gets progressively worse as you move up to 'faster' and 'fastest' to the point where it is very distracting and problematic. The 'off' setting seems to be the optimum here, offering actually pretty good response times and no overshoot at all. The other modes are just too aggressive and there's too much overshoot introduced, even at the lowest of the settings (Fast).

More Detailed Measurements - SmartResponse Off Having established that the overdrive 'off' mode seemed to offer the best response/overshoot balance we carried out our normal wider range of measurements as shown below: The average G2G response time was now more accurately measured at a pretty impressive 7.4ms. This was good for a VA panel. Rise and fall times were on average very comparable. The 0-255 (black > white) transition was the only slow transition measured, dragging the overall average down. Some response times actually reached very low levels, down to 2.3ms in the best case which was very impressive for a VA panel. The panel was living up to its spec of 8.5ms G2G quite easily, and even in some cases reaching down below the quoted 3ms G2G figure applicable for when you have SmartResponse enabled. If we evaluate the Response Time Compensation (RTC) overshoot then the results are pleasing and there is very little to be seen at all. A couple of the measured transitions showed a some very low levels of overshoot but nothing you'd notice in practice at all. A pleasing result here.

Display Comparisons The above comparison table and graph shows you the lowest, average and highest G2G response time measurement for a selection of screens we have tested with our oscilloscope system. There is also a colour coded mark next to each screen in the table to indicate the RTC overshoot error, as the response time figure alone doesn't tell the whole story. The response time performance of the BDM4065UC was impressive for a VA type panel, even when you consider we had to stick with the overdrive setting turned off to avoid a mass of overshoot artefacts. With a 7.4ms G2G average it was even a bit faster than the gamer-orientated Eizo Foris FG2421 (8.4ms average), as long as we consider all the recorded transitions. The Eizo had been affected by a couple of particularly slow transitions. If we were to ignore the most extreme cases on the FG2421 and on the BDM4065UC the response times would be far closer, and both would be around the 6.6 - 7.0ms G2G mark. Anyway, the point we are trying to make is that this is fast for a VA panel. Other VA panels like the BenQ GW2760HS and BenQ BL3200PT had been slower at around 10.8 - 10.9ms G2G. The Philips is even a bit faster than the best IPS panels we've tested. In the best examples, where no overshoot is introduced, IPS models like the Dell U2415 can reach down to around 8.6ms G2G average. A good TN Film model is of course still faster, reaching down to 2.9ms for instance in the example of the new Asus ROG Swift PG278Q (with moderate overshoot). They also have additional gaming features like higher refresh rates, blur reduction modes etc. For a VA panel this was a good response time performance though. The screen was also tested using the chase test in PixPerAn for the following display comparisons. As a reminder, a series of pictures are taken on the highest shutter speed and compared, with the best case example shown on the left, and worst case example on the right. This should only be used as a rough guide to comparative responsiveness but is handy for a comparison between different screens and technologies as well as a means to compare those screens we tested before the introduction of our oscilloscope method.

40 " 8.5ms G2G TP Vision VA (SmartResponse = Off) In practice the Philips BDM4065UC showed pretty low levels of motion blur, and no obvious ghosting. There was some some slight trailing in the best case images as you can see above but overall the movement felt quite good. There was no sign of any overshoot artefacts either which was pleasing in the SmartResponse = off mode. Of course you do need to keep in mind this is a VA panel, and so does not feel as snappy as a fast TN Film panel, and cannot offer the response time of that panel technology either. Other limiting factors also come into play including the refresh rate (limited to 60Hz here) and motion blur as a result of eye-tracking and the way LCD monitors operate. For an VA panel at 60Hz it is a decent result though.

40 " 8.5ms G2G TP Vision VA (SmartResponse = Off)

34" 5ms G2G LG.Display AH-IPS (Response Time = Middle)

28 " 1ms G2G Innolux TN Film (Overdrive = Faster)

31.5 " 8ms G2G Sharp IPS-mode IGZO If we compare the BDM4065UC to the other 4k res screens we've tested (well, 3840 x 1080 from the LG 34UM95) we can see some varying levels of performance from each panel technology. In practice the BDM4065UC performs fairly similarly to the LG 34UM95 with its IPS panel. The LG has slightly slower response times (9.5ms G2G) and in practice the blurring is a little more pronounced than on the Philips (7.4ms G2G). The Samsung U28D590D has a TN Film panel and has a 7.0ms G2G response time, only slightly faster than the Philips but nothing really to separate them in practice. The Dell UP3214Q is aimed at professional users and its IGZO panel has a 11.2ms G2G response time, showing a more apparent blur in moving images.

40 " 8.5ms G2G TP Vision VA (SmartResponse = Off)

27" 2ms G2G Chi Mei Innolux TN Film +144Hz (Trace Free = 60)

24" 2ms G2G AU Optronics TN Film + 120Hz (AMA = On)

23.5" 4ms G2G Sharp MVA + 120Hz We've also included a comparison above against 3 very fast 120Hz+ compatible screens we have tested. The other screens shown here are all aimed primarily at gamers and have various features and extras which make them more suitable overall for gaming. Firstly there is a comparison against the Asus VG278HE with its 144Hz refresh rate and fast response time TN Film panel. This showed very fast pixel response times and smooth movement thanks to its increased refresh rate. You are able to reduce the motion blur even more through the use of the LightBoost strobed backlight which we talked about in depth in our article about Motion Blur Reduction Backlights. Then there is a comparison against the BenQ XL2420T with another very fast TN Film panel and 120Hz refresh rate. This showed very low levels of motion blur, but some dark overshoot was introduced as a side-effect. Lastly there is the MVA based Eizo FG2421 screen with a fast response time (especially for the panel technology being used) and 120Hz refresh rate support. There is also an additional 'Turbo 240' motion blur reduction mode which really helps reduce the perceived motion blur in practice. While these pixel response tests from PixPerAn show the Philips to have pretty fast pixel transitions and freedom from any overshoot, there is something else going on as well here which can't be picked out by the camera. All of these other gaming models are running at 120Hz (or higher) refresh rates, which allows for improved 120fps+ frame rates and the support of 3D stereoscopic content as well. This can really help improve smoothness and the overall gaming experience so these screens still have the edge when it comes to fast gaming. Any additional extras to reduce perceived motion blur can also have a real benefit in practical terms, and again not easy to pick out with this camera method.





The responsiveness of the Philips BDM4065UC was pleasing, and actually very good for a VA panel. The average 7.4ms G2G response time couldn't of course compete with fast TN Film models, but for a VA panel it was good and also faster than IPS models available. The freedom from any overshoot problems was a major plus point but you do need to stick with SmartResponse set to off. The screen should be able to handle some fast gaming without problem, although those wanting to play fast FPS or competitive games may want to consider some of the more gamer orientated 120Hz+, TN Film based compatible displays out there, or perhaps something like the Eizo FG2421. Even better still would be models equipped with LightBoost systems or other motion blur reduction backlights for optimum motion blur elimination. The massive 40" screen size really comes in to its own when playing games. It adds a lot of immersion and you have a really huge area to view. You can comfortably sit a few metres back from the screen like you would with an LCD TV and play games. The Quad HD resolution is also very impressive for games, providing a very high resolution and a lot of detail. Images look sharp and crisp even up close. One big consideration you need to make is that the 3840 x 2160 resolution is likely to be a major drag on even high end graphics cards and PC systems when it comes to gaming. You really need to think about the type of game you want to play, the settings you want to use, and whether your system can handle outputting such a high resolution effectively. Your graphics card will also need to support DisplayPort 1.2 and you will need to enable this option in the OSD to obtain a full 60Hz refresh rate over DisplayPort. Other interfaces including the HDMI inputs are limited to 30Hz at 3840 x 2160. Don't forget that many gaming titles don't support this 4k resolution either, so that could be another issue. At least with those that do you don't need to worry about the size of fonts on a screen this size like you do on smaller 4k models. Some games don't handle scaling very well and so when it comes to the user interface a lack of scaling results in tiny text or hard to read maps etc. That's not a problem here though on the BDM4065UC. One option of course is to run the game at a lower resolution and let the screen scale it. That's probably the most sensible option in most cases and we know that the interpolation of lower resolutions like 1920 x 1080 is actually pretty good on this model. It does kind of defeat the point of having a 4k resolution in the first place though. If you have games which can natively support this resolution properly, they would look fantastic given the very high resolution and large screen size. External games consoles running at 1080p will still look fine of course, and the image is interpolated well, but you will certainly want to be sitting a normal TV viewing distance to play those we're sure.



Additional Gaming Features Aspect Ratio Control - The screen offers three options for hardware level aspect ratio control, available within the 'picture' section of the OSD menu. There are options for 'wide screen' (which fills the screen at a 16:9 ratio), 4:3 and 1:1 pixel mapping. This should offer adequate options for external devices and gaming needs.



Preset Modes - There is a defined 'game' preset mode available in the menu which seems to accentuate the sharpness of the image quite a lot. It might be a useful option to set up for your gaming needs and have a play around with.



Lag We have written an in depth article about input lag and the various measurement techniques which are used to evaluate this aspect of a display. It's important to first of all understand the different methods available and also what this lag means to you as an end-user. Input Lag vs. Display Lag vs. Signal Processing To avoid confusion with different terminology we will refer to this section of our reviews as just "lag" from now on, as there are a few different aspects to consider, and different interpretations of the term "input lag". We will consider the following points here as much as possible. The overall "display lag" is the first, that being the delay between the image being shown on the TFT display and that being shown on a CRT. This is what many people will know as input lag and originally was the measure made to explain why the image is a little behind when using a CRT. The older stopwatch based methods were the common way to measure this in the past, but through advanced studies have been shown to be quite inaccurate. As a result, more advanced tools like SMTT provide a method to measure that delay between a TFT and CRT while removing the inaccuracies of older stopwatch methods. In reality that lag / delay is caused by a combination of two things - the signal processing delay caused by the TFT electronics / scaler, and the response time of the pixels themselves. Most "input lag" measurements over the years have always been based on the overall display lag (signal processing + response time) and indeed the SMTT tool is based on this visual difference between a CRT and TFT and so measures the overall display lag. In practice the signal processing is the element which gives the feel of lag to the user, and the response time of course can impact blurring, and overall image quality in moving scenes. As people become more aware of lag as a possible issue, we are of course keen to try and understand the split between the two as much as possible to give a complete picture. The signal processing element within that is quite hard to identify without extremely high end equipment and very complicated methods. In fact the studies by Thomas Thiemann which really kicked this whole thing off were based on equipment worth >100,1000 Euro, requiring extremely high bandwidths and very complicated methods to trigger the correct behaviour and accurately measure the signal processing on its own. Other techniques which are being used since are not conducted by Thomas (he is a freelance writer) or based on this equipment or technique, and may also be subject to other errors or inaccuracies based on our conversations with him since. It's very hard as a result to produce a technique which will measure just the signal processing on its own unfortunately. Many measurement techniques are also not explained and so it is important to try and get a picture from various sources if possible to make an informed judgement about a display overall. For our tests we will continue to use the SMTT tool to measure the overall "display lag". From there we can use our oscilloscope system to measure the response time across a wide range of grey to grey (G2G) transitions as recorded in our response time tests. Since SMTT will not include the full response time within its measurements, after speaking with Thomas further about the situation we will subtract half of the average G2G response time from the total display lag. This should allow us to give a good estimation of how much of the overall lag is attributable to the signal processing element on its own.

Lag Classification

To help in this section we will also introduce a broader classification system for these results to help categorise each screen as one of the following levels: Class 1) Less than 16ms / 1 frame lag - should be fine for gamers, even at high levels

Class 2) A lag of 16 - 32ms / One to two frames - moderate lag but should be fine for many gamers. Caution advised for serious gaming and FPS

Class 3) A lag of more than 32ms / more than 2 frames - Some noticeable lag in daily usage, not suitable for high end gaming For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index. (Measurements in ms) Total Display Lag (SMTT 2) 24.0 Pixel Response Time Element 3.70 Estimated Signal Processing Lag 20.30 Lag Classification 2 Class 2 We have provided a comparison above against other models we have tested to give an indication between screens. The screens tested are split into two measurements which are based on our overall display lag tests (using SMTT) and half the average G2G response time, as measured by the oscilloscope. The response time is split from the overall display lag and shown on the graph as the green bar. From there, the signal processing (red bar) can be provided as a good estimation. The screen showed a total average display lag of 24.0 ms as measured with SMTT 2. Taking into account half the average G2G response time at 3.7ms ('off' SmartResponse overdrive setting), we can estimate that there is ~20.3 ms of signal processing lag on this screen. This is only just over 1 frame and represents a moderate level of lag. Should be ok for most gamers although some competitive or FPS type gamers might find it a bit too high.



Movies and Video The following summarises the screens performance in video applications: 40" screen size makes it a very decent size for an all-in-one multimedia screen, being comparable to many current LCD TV's in fact. Truly massive for a desktop display.

16:9 aspect ratio is more well suited to videos than a 16:10 format screen, leaving smaller borders on DVD's and wide screen content at the top and bottom.

3840 x 2160 resolution can support full Quad HD ("4k") resolution content, as well as 1920 x 1080 of course.

2x HDMI and 1x DisplayPort connections available, so good choices for modern DVD players, Blu-ray, consoles etc. Good to see HDMI included here.

Cables provided in the box for DisplayPort, HDMI, MHL/HDMI and VGA.

Glossy screen coating providing clean and clear images, similar to many modern TV's. The coating is not too reflective though.

Wide brightness range adjustment possible from the display, including high maximum luminance of ~280 cd/m 2 and a low minimum luminance of only 32 cd/m 2 . This should afford you very good control for different lighting conditions. Contrast ratio remains stable across that adjustment range as well.

Black depth and contrast ratio are excellent thanks to the VA panel at 4128:1 after calibration. Detail in darker scenes should not be lost as a result, and shadow detail should be very good. Certainly a strong point of this panel.

There is a specific 'movie' preset mode available for movies or video if you want but it felt quite similar to our calibrated user mode, if a little cooler. Might be useful if you need to have different settings or brightness for movies.

Good pixel responsiveness which should still be able to handle fast moving scenes in movies without issue. No overshoot issues which is pleasing as long as you stick to the 'off' overdrive setting.

Pretty wide viewing angles thanks to VA panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles. The vertical washing out of the image is a little restrictive so you will want to ensure you can view the screen head on. Thankfully unlike IPS panels there is no pale glow from an angle on dark content, so this technology is more suited to movie viewing.

Non-existent ergonomic adjustments available from the stand, so it's not the easiest to re-position for different viewing positions. You can move it side to side easily enough on the desk as it's quite light and has a thin profile, but the lack of tilt is a little disappointing.

No noticeable backlight leakage, and none from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here.

Basic 2x 7W integrated stereo speakers on this model which can handle some video sounds without problem.

Decent range of hardware aspect ratio options with aspect, wide, 4:3 and 1:1 pixel mappings modes available which should be fine for most uses.

Picture in picture (PiP) and Picture By Picture (PbP) are available with many different configurations available.

The screen does away with a lot of the video enhancement features you see on LCD TV sets, as this is a desktop monitor primarily.



Conclusion The first thing which strikes you about this screen is of course its size! It's truly a massive screen and some might argue that it's too big for every day desktop use. However, being so big does mean that the 3840 x 2160 quad HD resolution works very comfortably and you don't need to worry about OS and application scaling which is nice. The size and resolution make multi-tasking very easy, and the wide range of MultiView PiP/PbP options make split screening very practical. For gaming and movies the screen is excellent, offering a size equivalent to most TV's and something which you can comfortably use from a couple of metres away and still feel big, or from up close giving you impressive immersion. The VA panel performed very well overall, and we were impressed particularly by a couple of areas, The contrast ratio was excellent and clearly dark content and shadow detail is a strong point of this screen. The response times were also impressive for this panel technology, offering a decent gaming and movie experience for a VA panel. Default setup was decent enough and it's not hard to tweak some settings to correct the colour temperature. Unfortunately while the sRGB factory calibrated mode offered even more accurate setup, the preset was locked at 100% brightness making it unusable in practice. The uniformity correction mode worked well also which was pleasing, but the setup of gamma and white point need correcting in that mode through calibration. The VA panel offered pretty decent viewing angles as well, not as good as IPS but the freedom from the pale glow on dark content that you get from IPS was more beneficial on a screen this size. That lack of glow, the 4k resolution and the high contrast ratio made it very enjoyable for movie viewing. There were a couple of areas which were disappointing. The lack of any ergonomic adjustments from the stand was disappointing, but we suppose very comparable to modern TV's. The use of PWM for backlight dimming was a shame as well. All in all we thought we would never get used to a screen this size, but actually after a week or two of use it's very useable. The screen is a very interesting choice for that all in one display, which can be happily used as a decent desktop monitor and offer some very nice LCD TV-style gaming and movie experience. The price is very attractive as well, currently retailing in the UK at ~£689.99 (GBP). For a 4k screen so big, it's a very nice option. If you appreciate the review and enjoy reading and like our work, we would welcome a donation to the site to help us continue to make quality and detailed reviews for you.

Pros Cons Huge screen size and Quad HD resolution very nice for a whole variety of uses Very limited stand with no ergonomic adjustments offered Excellent black depth and contrast ratio thanks to VA panel PWM used for backlight dimming Surprisingly good response times sRGB factory calibrated mode locked at 100% brightness

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