Author: Adam Simmons

Date published: Janaury 12th 2019



Many gamers find the immersive experience and enhanced in-game Field of View (FOV) offered by UltraWide resolutions such as 3440 x 1440 to be a very attractive thing. The extra real-estate compared to the narrower 16:9 equivalent resolution is also useful on the desktop and some movie content also benefits. The LG 34GK950F (or 34GK950F-B owing to the black rear) of the ‘UltraGear’ series combines a curved high refresh rate 3440 x 1440 ‘Nano IPS’ panel with support for AMD FreeSync 2 on compatible GPUs and systems. The monitor also offers basic HDR support. We put this monitor through its paces in our usual gauntlet of tests, seeing how it performs at a range of tasks including gaming.





This model features a 34” LG ‘Nano IPS’ (In Plane Switching) panel. The ‘Nano’ in this case refers to the use of an enhanced phosphor backlight, specifically a WLED solution with a ‘KSF phosphor’ layer (K2SiF6 doped with Mn4). This enhances the colour gamut but does not change other characteristics of the IPS panel. It also features a 3440 x 1440 resolution and supports 144Hz natively. Some of the key ‘talking points’ have been highlighted in blue below.



Screen size: 34 inches

Panel type: LG Display LM340UW5 Nano IPS (In-Plane Switching) LCD

Native resolution: 3440 x 1440

Typical maximum brightness: 400 cd/m²

Colour support: 1.07 billion (8-bits per subpixel plus dithering)

Response time (G2G): 5ms (1ms MPRT with Motion Blur Reduction)

Refresh rate: 144Hz (variable, with Adaptive-Sync)

Weight: 7.9kg

Contrast ratio: 1000:1

Viewing angle: 178º horizontal, 178º vertical

Power consumption: 95W typical

Backlight: WLED (White Light Emitting Diode)

Typical price as reviewed: £1100 ($1200 USD)

The monitor adopts the exterior design seen on some of the company’s other recent gaming monitors, such as the 32GK850G. The screen is of course significantly wider, adopts a 1900R (moderate) curve and has somewhat thicker bezels. The bezels are a dual-stage (‘4-side borderless’) design with very slim hard outer component and a slender panel border surrounding the image. These are ~10.5mm (0.41 inches) at the top and sides and ~14mm (0.55 inches) at the bottom. The monitor has a Y-shaped stand composed predominantly of matte black plastic. There is a matte red stripe at the rear face of the stand base, but this is barely visible from a normal viewing position in front of the monitor. The screen surface is light matte anti-glare, as explored later.





The OSD (On Screen Display) is controlled by a joystick facing downwards in the centre of the bottom bezel, illuminated by a power LED. This can’t be seen from a normal viewing position and can be disabled in the OSD if preferred. If the ‘Power LED’ is set to ‘On’ in the ‘General’ section of the OSD, it glows red when the monitor is on and flashes red when it enters a low power state (signal to the system is lost). To the immediate left of this there is a K-Slot. The OSD explored in the video below.





From the side the screen is fairly slim overall – ~23mm (0.91 inches) At thinnest point, lumping out centrally towards the stand attachment point. The monitor is mainly matte black plastic from this angle, with the aforementioned red elements on the base of the stand more noticeable from here. The stand offers good ergonomic flexibility; tilt (5° forwards, 15° backwards), swivel (20° left, 20° right) and height adjustment (110mm or 4.33 inches) . The total depth of monitor including stand is ~295mm (11.61 inches), so it’s somewhat shallower than some displays of this size which will be welcomed by those with relatively little desk depth. At lowest screen height, the bottom edge of the screen clears the desk by ~104mm (4.09 inches), with the top of the screen ~464mm (18.27 inches) clear of the desk.







The rear of the screen is again dominated by matte black plastic, with a few red elements. In addition to those already mentioned at the rear faces of the stand base, there’s a red ring at the top of the stand neck and a radial spread of red notches around the stand attachment point and port area. There’s also a red ring surrounding these notches. These notches are decorative and do not house the ‘Sphere Lighting’ system found on the ‘G’ model. There’s a quick-release mechanism to unlatch the screen from the stand, allowing an alternative 100 x 100mm VESA compatible solution to be used for mounting. The port area is located to the right of the stand attachment point, in a recessed area with the ports facing backwards. These are; DP 1.4, 2 HDMI 2.0 ports, 2 USB 3.0 ports (plus upstream), a 3.5mm headphone jack, a service port and a DC power input (external power brick). A clip-on cable tidy is also included, which sits towards the top of the stand neck.





3440 x 1440 @ 144Hz is supported via DP 1.4 on compatible GPUs from both AMD and Nvidia. DP 1.2 is limited to 3440 x 1440 @ 120Hz maximum, whilst HDMI 2.0 is limited to 85Hz maximum on this model. Compatible AMD GPUs and systems also support FreeSync (via Adaptive-Sync) over DP or HDMI. HDR is also supported on compatible GPUs and systems, including those from Nvidia, via DP and HDMI. A power cable, DP cable, HDMI cable and USB 3.0 cable are included as standard.





The image below is a macro photographs taken on Notepad with ClearType disabled. The letters ‘PCM’ are typed out to help highlight any potential text rendering issues related to unusual subpixel structure, whilst the white space more clearly shows the actual subpixel layout alongside a rough indication of screen surface. A light (or ‘very light’, depending on how you choose to classify it) matte anti-glare screen surface is employed, with a smooth surface texture. This gives a relatively smooth look to the image without imparting any real graininess and aids the vibrancy potential of the monitor. Whilst also maintaining decent glare-handling. Regardless of the anti-glare properties, you should always try to position the screen appropriately and control your ambient lighting where possible to avoid unwanted glare.







As shown above, the monitor uses the usual RGB (Red, Green and Blue) stripe subpixel layout. This is the default ‘expected’ by modern operating systems such as Microsoft Windows and Apple’s MacOS. Apple users needn’t worry about text fringing caused by less common subpixel layouts and Windows users don’t necessarily need to run ClearType. They may still wish to run the ClearType wizard and adjust according to preferences, however. The subpixel layout and arrangement is quite normal and we had no subpixel-related concerns related to sharpness or text clarity on this model.





The 34GK950F has several ‘Game Mode’ image presets; ‘Gamer 1’, ‘Gamer 2’, ‘FPS’, ‘RTS’, ‘Vivid’, ‘Reader’, ‘HDR Effect’ and ‘sRGB’. ‘Gamer 1’ and ‘Gamer 2’ are fully customisable, allowing access to all OSD settings, whereas the remaining presets lock off various settings such as ‘Sharpness’, ‘Gamma’, ‘Color Temp’ and ‘Response Time’. The table below shows key readings alongside general observations made by eye using familiar images and applications. Gamma readings were taken using a DataColor Spyder5ELITE, whilst a BasICColor SQUID 3 (X-Rite i1Display Pro) was used for white point measurement. The monitor was left in its ‘Plug and Play’ state and left to run for over 2 hours before observations or readings were made. It was connected to a Windows 10 system without additional drivers or ICC profiles specifically loaded. The system primarily used an Nvidia GTX 1080 Ti, although additional testing was performed using an AMD Radeon RX 580. Testing AMD FreeSync, for example, which is not possible on an Nvidia GPU. Unless otherwise stated, assume that settings were left at default (including ‘Contrast’. The exception was that refresh rate was set to 144Hz, but this didn’t affect our observations on this table or static image quality elsewhere in the review. When viewing the figures in this table, note that for most PC users ‘6500K’ for white point and ‘2.2’ for gamma are good targets to aim for.

Straight from the box the monitor was very bright with a noticeable cool-tint, but was otherwise well-balanced. The image was unmistakably vibrant, with strong saturation but good shade variety maintained. With some tweaking in the OSD a more comfortable brightness and more appropriate white point could be achieved. The monitor also includes a factory calibration report to show the targets achieved at the factory using factory equipment and measurement conditions. Unfortunately, our factory calibration report was in too poor a state to read or scan properly so we won’t include it in the review. Regardless of this, we can at least agree that the gamma tracking was well-tuned in the factory and indeed following the adjustments made to our ‘Test Settings’. This is shown below, with strong adherence to the desirable ‘2.2’ curve. Given the intended uses of the monitor, inter-unit variation and pleasing performance following OSD tweaking alone we will not be providing any ICC profiles for this model or using them in the review.



Gamma 'Test Settings' The monitor also included a fairly effective Low Blue Light (LBL) setting called ‘Reader’. This provided a fair reduction in the blue colour channel (and luminance) compared to the factory defaults. This is useful in the hours leading up towards bed where blue light exposure should be minimised, as it’s disruptive to sleep hormones and keeps the body alert. Some users prefer LBL settings at other times, too. It also significantly reduced contrast, which is intentional as it is supposed to reduce the amount of time your eyes spend adjusting to changing light levels from the monitor. As the changes in light levels are far more subtle. That’s the theory, but of course ambient light levels can also change significantly unless they are very tightly controlled. And we didn’t find any viewing comfort benefits from this approach ourselves. We therefore made our own modified LBL setting. We used our ‘Test Settings’ as a base but changed the colour channels to R= 50, G= 38, B= 25. This achieved more significant blue light reduction than ‘Reader’, without the same drop in contrast. It was also very convenient to switch between this and our regular ‘Test Settings’ as they could both be stored independently using the fully customisable ‘Gamer 1’ and ‘Gamer 2’ presets. These allow you to customise everything on the ‘Game Adjust’ and ‘Picture Adjust’ OSD sections and recall those preferences.



Test Settings For our ‘Test Settings’ we significantly lowered brightness and made some changes to colour channels. This achieved a more comfortable image with more appropriate brightness and white point. As usual, note that individual unit and preferences vary, so these settings should only be used as a guide and not considered optimal for all users. Assume any setting not mentioned, including ‘Contrast’ and ‘Gamma’, was left at default. We also disabled the ‘SMART ENERGY SAVING’ feature as this causes brightness fluctuations according to the content being displayed. We’ve also included the ‘Response Time’ setting and refresh rate used for reference, too. Note that these settings only apply to SDR testing, which is the bulk of our review. HDR has separate settings associated with it – we explore HDR separately in the designated section. We had to make a small GPU driver tweak on our GPU when the monitor was connected via DP and FreeSync was set to ‘Extended’. There is a small colour processing issue by default which means things look noticeably undersaturated. You simply need to open ‘Radeon Settings’, navigate to ‘Display’ – ‘Color’ (little icon towards the top right) and press the ‘Color Temperature’ toggle so it reads ‘6500K’ instead of ‘Automatic’.





Game Mode= Gamer 1 Game Mode= Gamer 1 Brightness= 35 (according to preferences and lighting) R= 50 G= 44 B= 46 FreeSync= Extended (AMD GPU only) Response Time= Faster SMART ENERGY SAVING= Off Refresh rate (Windows setting)= 144Hz

Contrast and brightness Contrast ratios A BasICColor SQUID 3 (X-Rite i1Display Pro) was used to measure the luminance of white and black using a range of monitor settings, including those analysed in the calibration section. Static contrast ratios were calculated using these figures, as shown in the table below. Black highlights indicate the highest white luminance, lowest black luminance and peak contrast ratio recorded (HDR and MBR disabled). Blue highlights show the results under our ‘Test Settings’ and also with HDR active. Assume any setting not mentioned was left at default, with the exceptions already noted in the calibration section. Note that refresh rate was set to 144Hz, including for the ‘1ms Motion Blur Reduction’ (1ms MBR) testing, and that ‘SMART ENERGY SAVING’ was disabled in all cases. Monitor Settings White luminance (cd/m²) Black luminance (cd/m²) Contrast ratio (x:1) 100% brightness (Factory Defaults) 402 0.4 1005 80% brightness 340 0.34 1000 60% brightness 277 0.28 989 40% brightness 212 0.21 1010 20% brightness 143 0.14 1021 0% brightness 72 0.07 1029 HDR* (100% brightness) 390 0.38 1026 HDR* (50% brightness) 236 0.23 1026 HDR* (0% brightness) 70 0.07 1000 Gamma = Mode 1 448 0.41 1093 Gamma = Mode 3 447 0.41 1090 Gamma = Mode 4 447 0.41 1090 Gamer 2 402 0.4 1005 FPS 349 0.41 851 RTS 349 0.41 851 Vivid 373 0.41 910 Reader 150 0.91 165 Relaxing evening viewing 136 0.2 680 HDR Effect 451 0.41 1100 sRGB 208 0.22 945 1ms MBR (100% brightness) 240 0.24 1000 1ms MBR (50% brightness) 146 0.15 973 1ms MBR (0% brightness) 47 0.05 940 Test Settings 165 0.19 868

*HDR measurements were made using this YouTube HDR brightness test video, running full screen at ‘1440p HDR’ on Google Chrome. The maximum reading from the smallest patch size (measurement area) that comfortably covered the entire sensor area and colorimeter housing was used for the white luminance measurement, which was ‘4% of all pixels’ in this case. The black luminance was taken at the same point of the video with the colorimeter offset to the side of the white test patch, equidistant between the test patch and edge of the monitor bezel.

The average static contrast with only brightness adjusted was 1008:1, with a maximum recorded value of 1100:1. This is much in-line with our expectations given the panel used. The ‘HDR Effect’ setting and changing gamma mode yielded contrast ratios at the upper end of the measurement range. The lowest value recorded was with the ‘Reader’ mode active, which purposefully minimises contrast – to 165:1. Our ‘Relaxing evening viewing’ settings reduced contrast a bit but certainly not as much, hitting 680:1. Our ‘Test Settings’ yielded 868:1, which is quite respectable after the adjustments made. The peak luminance recorded on this table was a rather bright 451 cd/m² (using ‘HDR Effect’), whilst the minimum white luminance recorded (without HDR or MBR active) was 72 cd/m². This yielded a luminance adjustment range of 379 cd/m², with a good bright maximum and a reasonably but not exceptionally dim minimum. The peak luminance recorded with MBR active was 240 cd/m², with a minimum white luminance of 47 cd/m². So a good brightness adjustment range as far as such strobe backlight settings go.

Activating HDR did nothing to enhance contrast. This wasn’t at all unexpected given that it only VESA DisplayHDR 400 certified (as explored later) and lacks any sort of local dimming on the backlight. We tested various presets with HDR active and none yielded any enhancement to contrast, with a significant enhancement there requiring local dimming for the backlight and therefore physically impossible on this model. The experience was consistent whether tested using our AMD or Nvidia GPU and whether HDMI 2.0 or DP 1.4 was used. The monitor also offers a Dynamic Contrast setting called ‘DFC’ (Dynamic Fine Contrast). This allows the backlight to adjust according to the overall brightness levels of the scene being displayed. It can be activated under SDR (Standard Dynamic Range) and more or less mimics the standard behaviour of the monitor’s backlight for HDR content. As we’ve established, there is no local dimming. So this setting adjusts the entire backlight according to the average values of the content brightness. With this setting active you can set your brightness in the OSD, which limits the upper range of operation. That’s a good flexibility to have. In general we found the effect rather subtle as far as Dynamic Contrast settings go. So it wasn’t overly distracting. But we didn’t find it really added anything to the experience, either.





PWM (Pulse Width Modulation)

This monitor does not use PWM (Pulse Width Modulation) at any brightness level. Instead, DC (Direct Current) is used to regulate backlight brightness at all levels. The backlight is therefore flicker-free, which will come as welcome news to those worried about potential side-effects from PWM usage. The exception to this is with the ‘1ms Motion Blur Reduction’ feature active. This is a strobe backlight setting that causes the backlight to flicker at ~144Hz.





Luminance uniformity