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.

The screen uses overdrive technology to boost pixel transitions across grey to grey changes as with nearly all modern displays. The part being used is a LG.Display LM375QW2 Nano IPS technology panel . Have a read about response time in our specs section if you need additional information about this measurement.

There are 2x USB 3.0 ports on the back of the screen which are reasonably easy to access. There are also no other extras like ambient light sensors, motion sensors or card readers on this screen which are sometimes useful for office-type uses. There is a decent enough range of ergonomic adjustments from the stand with a good tilt and height adjustment offered. We don't need rotation on a screen this size and format, but we did miss side to side swivel a bit.

There are no blue light filter options offered on this screen, but there is a "reader" preset mode in the menu. This makes the image warmer and more yellow, but might be more comfortable for lots of text work or later at night. The white point changes from our calibrated 6500k to 5191k when you switch to the reader mode. We have included the spectral distribution graphs for each mode above, where you can see this reduces the blue light output as a result of the warmer colour temperature.

The brightness range of the screen was good, with the ability to offer a luminance between 458 and 59 cd/m 2 . This gives you flexibility even in darker room conditions and low ambient light conditions. A setting of 15 in the OSD brightness control should return you a luminance close to 120 cd/m 2 out of the box. The brightness regulation is controlled via a flicker free backlight, without the need for Pulse Width Modulation (PWM), and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry. There was no audible buzzing from the screen, even when conducting specific tests which can sometimes cause issues.

The out of the box gamma setup was decent here although the white point needs some minor correction as it's a bit too cool, but that's easy to do. The screen operates in its normal wide gamut mode by default, but there is a useable sRGB emulation mode which carries a decent factory calibration available too. That mode too is a little cool, but not by anything major. It's useful to see sRGB mode included for those wanting to work specifically with standard gamut content outside of a colour managed workflow.

One of the key selling points of ultra-wide screens like the this is it's high resolution and large screen size. The 3840 x 1600 display offers a sharp but comfortable picture. Its pixel area is about 2.2 times larger than an Ultra-Wide Full HD 21:9 monitor (2560 x 1080), and about 3 times larger than a Full HD 16:9 monitor (1920 x 1080). It provides an efficient environment for using Microsoft Office programs and internet browsing, and split screen working is a pleasure. You can comfortably have the screen split in to 3 vertical sections if you want which is very nice. Thankfully the high resolution is of a very comfortable size on the 37.5" panel, with a 0.229mm pixel pitch it is very comparable to a 27" 2560 x 1440 monitor (0.2331mm) and the popular ultra-wide 34" 3440 x 1440 displays (0.2325mm). This means you are basically getting a slightly wider and slightly higher desktop area than the 34" models, with a similar font size. If you're coming from a lower resolution / larger pixel pitch you may still find the fonts look quite small to start with, but like the 27" 1440p models out there you soon get used to it. We continue to enjoy the curved format of these displays for day to day office work. It just felt more comfortable than a flat screen on a model as wide as this, bringing the corners a bit nearer to you. You didn't really notice the curve in normal use but we liked the feel. Probably down to user taste, so if in doubt try and see one in person. The extra vertical room compared with a 34" ultrawide was useful for office uses as well, it's not much but you do notice the extra room.

Note: if you want to test your own screen for backlight bleed and uniformity problems at any point you need to ensure you have suitable testing conditions. Set the monitor to a sensible day to day brightness level, preferably as close to 120 cd/m 2 as you can get it (our tests are once the screen is calibrated to this luminance). Don't just take a photo at the default brightness which is almost always far too high and not a realistic usage condition. You need to take the photo from about 1.5 - 2m back to avoid capturing viewing angle characteristics, especially on IPS-type panels where off-angle glow can come in to play easily. Photos should be taken in a darkened room at a shutter speed which captures what you see reliably and doesn't over-expose the image. A shutter speed of 1/8 second will probably be suitable for this.

We also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. There was some slight backlight clouding in the top right hand corner but no major leakage. This was very hard to see during normal usage though from a normal viewing position but became a little more noticeable from a wider viewing angle when viewing darker content.

We have seen some early adopters mention a "vignetting" effect on the screen, where the corners appear a bit darker than the central regions of the screen. They report that this is not really evident in practice but is easier to spot on solid colour blocks. We tested our sample for this effect and couldn't detect anything unusual to be honest. Along the bottom edge of the screen was a little darker, probably due to where the panel is housed in the enclosure and lower bezel but this was definitely not something you could see in normal use. We didn't see any issues with the corner regions being darker on our sample apart from the drop in the top left corner measured above.

Luminance uniformity of the screen was good on our sample, with 88% of the screen within a 10% deviance of the centrally calibrated area. In the upper left hand corner the screen was a little darker and there was a modest drop in luminance down to 96 cd/m 2 in the most extreme case (-25%), but this was only in one area.

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.

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 36 points across the panel on a pure white background. The measurements for luminance 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/m 2 . 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.

On a black image there is a characteristic pale glow introduced to the image when viewed from a wide angle, commonly referred to as IPS glow. This type of glow is common on most modern IPS-type panels and can be distracting to some users. If you view dark content from a normal head-on viewing position, you can actually see this glow as your eyes look towards the edges of the screen. Because of the sheer horizontal size of this 37.5" panel, the glow towards the edges is more obvious than on small screens, where there isn't such a long distance from your central position to the edges. Some people may find this problematic if they are working with a lot of dark content or solid colour patterns. In normal day to day uses, office work, movies and games you couldn't really notice this unless you were viewing darker content. If you move your viewing position back, which is probably likely for movies and games, the effect reduces as you do not have such an extreme angle from your eye position to the screen edges. The glow effect was a little less than on flat ultra-wide screens as the curved nature created a smaller angle between your eyes and the edges of the screen.

Viewing angles were very good as you would expect from an IPS panel overall. Horizontally there was very little colour tone shift until wide angles past about 45°. A slight darkening of the image occurred horizontally from wider angles as you can see above as the contrast shifted slighting. Contrast shifts were slightly more noticeable in the vertical field but overall they were very good. The screen offered the wide viewing angles of IPS technology and was free from the restrictive fields of view of TN Film panels, especially in the vertical plane. It was also free of the off-centre contrast shift you see from VA panels and a lot of the quite obvious gamma and colour tone shift you see from some of the modern VA panel type offerings.

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Contrast ratio was the weakest area of this screen, much like the smaller 27" LG 27GL850 . After calibration we achieved 828:1 which is by no means terrible, it's just not as high as some other IPS panels can reach nowadays up to around 1000:1 - 1200:1. It's a bit more typical of a TN Film panel contrast ratio. If you want something with a much higher contrast ratio then VA panels can offer that - although sacrifice then in other areas like viewing angles and responsiveness.

Default setup of the screen out of the box was pretty decent overall. There was a pretty decent gamma which was good news as this is often the hardest thing to correct without a calibration device. White point was a little too cool, but easy to correct through some simple RGB control changes in the native gamut mode. There was an available sRGB emulation mode which worked well and offered a very low dE. The only issue with that mode was that it was also a bit too cool, and it's not possible to correct that via the OSD menu as the RGB controls are greyed out.

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.

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. We have divided the table up by panel technology as well to make it easier to compare similar models. 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 some (gamma especially) are not as easy to change accurately without a calibration tool.

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.

The calibration corrected the small gamma deviance we'd seen at default settings, now returning a 2.2 average. The white point was also now corrected to 6513k which was very good. The brightness control adjustment had reduced the luminance to a comfortable level now, and the screen maintained a similar static contrast ratio of 828:1 with a small drop from the profile corrections. Colour accuracy of the resulting profile was excellent, with dE average of 0.5 and maximum of 1.2. Gradients were mostly smooth with a little bit of banding and gradation in the darker shades.

The OSD settings were adjusted as shown in the table above, as guided during the calibration process and measurements. These OSD changes allowed us to obtain an optimal 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 .

We used the X-rite i1 Pro 2 Spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An X-rite i1 Display Pro Plus colorimeter was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

We could only really correct the white point and brightness here, and the dE readings should be ignored in the above report as they are comparing the wide gamut colours against an sRGB reference. Ignoring that, these optimal settings have helped correct the white point to approximately 6500k and reduce the brightness to a more comfortable level. The contrast ratio remained consistent and thankfully wasn't negatively impacted any further.

We also measured the screen after adjusting only the OSD controls, to obtain the optimal setup without a full calibration, and without the use of an ICC correction profile. This represents what could be achieved through just simple changes to the monitor itself, and also what you could expect when working with content outside of an ICC profile managed workflow. The early stages of our calibration software helped identity these optimal OSD settings.

We also tested the screen in the sRGB preset mode as shown above. This provided a decent emulation of the smaller colour space, cutting back any oversaturation you might see when trying to use sRGB content on this native wide gamut screen. We measured a 97.7% sRGB coverage which was very good. Gamma and white point remained pretty much as they had before, the main deviance being in the overly cool white point (10% out). Luminance had dropped since the OSD brightness control was now set at a more modest 32% by default. You thankfully can change this brightness control yourself which makes this a useable mode. However, you don't have access to the gamma, colour temp or RGB controls in this preset, so it's tricky to change the white point unfortunately. dE measurements were very good, and this is representative of the factory calibration LG have completed on this screen. We measured 1.1 dE average, and only 1.8 maximum which was excellent.

Luminance at the default 75% brightness level was recorded at a bright 351 cd/m 2 which is too high for prolonged general use, you will need to turn that down. The black depth was 0.40 cd/m 2 at this default brightness setting, giving us a mediocre static contrast ratio of 868:1. Colour accuracy measurements should be ignored here as they are comparing the produced wider gamut display colours against an sRGB reference which will always lead to errors. When testing the screen with colour gradients there nice smooth transitions with only a small amount of gradation in darker tones.

White point was measured at 7194k, being a bit too cool compared to our target of 6500k (11% deviance). We did also measure the other modes and found that the warm mode was the same as this default setup = 7194k, medium was cooler at 8448k, and cool was cooler still at 10,673k. You can adjust the RGB levels though in this default 'custom' mode which should allow easy correction of the white point anyway in the native gamut mode.

Default gamma was recorded at 2.3 average with a small 6% deviance from the target which was reasonably close to the target. There are other gamma modes in the OSD which we also tested for completeness as below:

The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) extends a fair way beyond the sRGB reference space (orange triangle), mostly in green and red shades. We measured using ChromaPure software a 130.9% sRGB gamut volume coverage which corresponds to 96.5% of the DCI-P3 reference and 69.2% of the Rec.2020 reference. There is an sRGB emulation mode available which we will test in a moment.

The display was set with a pretty bright 75% brightness which was uncomfortable to use for long periods. You will want to turn that down as with most screens. The colour balance and whites felt a bit cool but you could tell that the screen was offering a wide colour gamut by default, with colours looking more vivid and saturated than typical sRGB screens. We went ahead and measured the screen with our i1 Pro 2 spectrophotometer.

dE average / maximum - we aim for 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.

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

Colour space coverage volumes - we also measure using a piece of software called ChromaPure the colour space (gamut) volumes produced by the backlight in comparison to the sRGB, DCI-P3 and Rec.2020 colour spaces. sRGB is the most commonly used colour space so it is important to have a decent coverage from the screen here. If the colour space is >100% sRGB then the screen can produce a wider colour gamut, often reaching further in to the wider gamut DCI-P3 (commonly used for HDR) and Rec.2020 reference spaces.

CIE Diagram - confirms 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. Usually shown as a comparison against the common sRGB space

We restored our graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using our new X-rite i1 Pro 2 Spectrophotometer combined with LaCie's Blue Eye Pro software suite. An X-rite i1 Display Pro Plus colorimeter was also used to verify the black point and contrast ratio since the i1 Pro 2 spectrophotometer is less reliable at the darker end.

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.



Response Times and Refresh Rate

There's various things you need to consider when it comes to response times and gaming, particularly on a display with high refresh rate support. Gaming screens invariably give you a control for the overdrive impulse in the OSD menu which can help you tweak things, but response time performance and overshoot levels can vary depending on the active refresh rate. This behaviour is often different depending on whether the screen is a traditional Native G-sync screens (with hardware module) or whether it's an adaptive-sync screen (FreeSync and G-sync support), and not all screens behave in the same way. We always try to test each variable in our reviews but the key considerations you need to make are:

Performance at 60Hz - this is important if you want to use an external games console (or other device like a Blu-ray player etc) which typically run at 60Hz. Response time performance may well be different than at the higher refresh rates supported, and you may need a different overdrive setting for optimal experience.

Performance during VRR (Variable Refresh Rate) - bearing in mind that the refresh rate will fluctuate anywhere from 1Hz up to the maximum supported by the screen (e.g. 1 - 144Hz on a 144Hz display). It's important to understand if the response times and overshoot will vary as the refresh rate changes. There may be a need to switch between different overdrive settings in some cases, depending on your usually attained refresh rate output and graphics card capability. This can sometimes become fiddly if your refresh rates fluctuate a lot, especially between different games, so it's always easier if you can leave a display on a single overdrive setting which is suited to the whole range. Some screens also feature "variable overdrive" which helps control the response times and overshoot depending on the active refresh rate. This is particularly apparent with traditional G-sync module screens.

Performance at fixed refresh rates including maximum - this is important for those who have a powerful enough system to consistently output a frame rate to meet the max refresh rate capability of the screen. They may want to run at max refresh rate without VRR active, or even is VRR is active they may know they will be consistently at the upper end of the range. Many gaming screens show their optimal response time performance at the maximum refresh rate. Knowing the performance at high fixed refresh rates may also be applicable if you want to use any added blur reduction backlight which typically operate at a fixed refresh rate.

Whether the response times can keep up with the frame rate - you will also want to consider whether the response times of the panel can consistently keep up with the frame rate. For instance a 144Hz screen sends a new frame to the display every 6.94ms, so the pixel response times need to ideally be consistently and reliably under this threshold. If they are too slow, it can lead to added blurring in practice and sometimes make the higher refresh rates unusable in real life. We consider this in our analysis.



There is a Response Time setting in the OSD which controls the overdrive level. We carried out some initial response time measurements and visual tests in each of the overdrive settings, and at a range of refresh rates. There are 4 levels available - Off, Normal, Fast and Faster Key Quick Information Box The fastest IPS panel we've measured to date

Excellent response times in optimal 'Fast' mode which can keep up with even the max 175Hz frame rate

Variable overdrive supported

High refresh rate improves motion clarity significantly

Support for VRR for both NVIDIA and AMD systems is very welcome

1ms G2G spec not useable in practice, but it's plenty fast enough without it!

Optimal Fast Setting

We carried out a range of visual tests and it was fairly easy to spot which mode was optimal. There were some minor improvements as you increased the response time control from Off > Normal > Fast, and you could see some slight improvements in motion clarity and reduction in motion blur. We will talk about the 'Faster' setting in a moment in a bit more detail, but that produced noticeable overshoot with dark and pale halos being very visible.

We were impressed by the low levels of blur even with Response Time set to 'Off' actually. The 'Fast' setting offered the optimal performance though. We then measured the response times in this mode across a range of increasing refresh rates.



As you increased the refresh rate the response times were improved a little each step. This is a result of the "variable overdrive" capability of the Native G-sync hardware module, and one of the benefits in using this technology. Motion clarity improved noticeably as the refresh rate increased which was to be expected and it was great to see high refresh rate support offered here for gaming needs. That's well beyond the capability of previous 37.5" screens we've tested in the past. There was very little overshoot at all, with a bit more being measured at the lower refresh rates. The variable overdrive is turning the overdrive impulse down a little as refresh rate lowers, which is why the G2G figures get a little slower, and this is done to help ensure the overdrive is kept under control. You couldn't see any halos or artefacts from any of this overshoot in practice. We were very impressed by the very low response times of this panel and motion clarity thanks to the high refresh rates.

Achieving the 1ms G2G Spec?

This leads to the obvious question then of how the 1ms G2G spec has been achieved. The answer, probably unsurprisingly, is that it is only possible if you switch the monitor to the maximum 'Faster' response time setting which is documented on many of the LG.com regional pages and in the spec sheet. We took measurements again at 175Hz in this mode:

The behaviour and performance was very similar to what we saw from the LG 27GL850 when we tested that. As you can see, the overall response times have improved noticeably, down from 3.8ms G2G in the 'Fast' mode to a very low 2.7ms G2G average here. Some transitions do reach almost as low as 1ms, the best we measured was 1.1ms so the screen is living up to the spec basically which says it can reach 1ms in the 'Faster' mode. However, this is at the cost of some massive levels of overshoot. They weren't quite as crazy as on the 27GL850 but they were still too high for practical usage! In practice there are some obvious and distracting pale and dark halos behind moving objects, and it makes this Faster mode impractical to use.



The variable overdrive served to lower the response times as the refresh rate varied, and also the overshoot levels. In practice it was harder to see the overshoot at the lower refresh rates like 60Hz, but there's still enough there to make the 'Fast' mode a better option.



0-150-0 transition measurement in 'Faster' Response Time mode at 175Hz

showing large 136% overshoot on the rise time (scale 20ms)



Pursuit camera photos of the 'Faster' Response Time mode 175Hz showing the noticeable overshoot artefacts



We also took some photos using a pursuit camera setup to give you an indication of the real perceived motion clarity in this 'Faster' Response Time mode, at 175Hz refresh rate. This is to demonstrate the high levels of overshoot you can see in this mode.

We will repeat what we said in the 27GL850 review. Obviously this 1ms G2G spec is complete marketing, and is not something achievable in practice at all without serious side-effects. There's no denying that the panel is fast anyway, even in the more modest and sensible 'Fast' mode, and we don't want to take anything away from it's performance in what we consider the optimal 'Fast' mode as it's very impressive. To be honest we'd have rather LG had stuck with a more traditional response time spec like 4 ms G2G and delivered a great performance in that range, than push unrealistic and unachievable marketing figures that don't live up to the hype. What makes it worse is that this has been "verified" and "certified" by Underwriter Laboratories (UL) as an independent third party which for us, really brings in to question their credibility. Until the 27GL850 model we'd not come across them before in the monitor market, but we would hope that in the future they consider the true overall view of these things before certifying crazy figures that don't work. Sure, you can reach 1ms G2G on the 27GL850 and on this panel, but if it's at the cost of very high levels of overshoot what is the point?





Refresh Rate Considerations and Overclocking

Refresh Rate Colour Depth Supported Colour Range 120Hz and below 10-bit Full RGB Native maximum 144Hz 8-bit Full RGB Overclocked 160Hz 8-bit Full RGB Overclocked 175Hz 10-bit Limited 4:2:2 Chroma

The 38GL950G supports a native 144Hz refresh rate maximum from the panel. Thanks to the use of a hardware G-sync module, it is also possible to overclock the refresh rate up to 175Hz. This is beyond what is possible from a normal scaler screen (i.e. without the G-sync module), as evident by the forthcoming LG 38GN950 model which features FreeSync and only supports up to 160Hz via an overclock. If you want to use refresh rates beyond 144Hz then you have to enable the overclocking feature in the OSD menu. Once you have, the new refresh rates appear in Windows to select.

There are some bandwidth limitations of the DisplayPort 1.4 interface as with other top-end gaming screens that need to be accounted for. To drive the screen at such a high 3840 x 1600 resolution you have to make some sacrifices to the colour levels depending on the refresh rate. For refresh rates up to 120Hz you can run the screen at full RGB range and at 10-bit colour if you want. Keep in mind that you'd only really need to run at 10-bit colour depth if you have relevant software and games that can make use of this, otherwise 8-bit colour depth is more than fine. In fact you will probably be very hard pressed to see any practical difference between an 8-bit or 10-bit colour depth in these kind of uses anyway. Up to 120Hz is the easy part as that falls within the DP 1.4 bandwidth limit nicely.

For anything above 120Hz you will have to drop the colour levels in one of two ways. The best way, without leading to noticeable image degradation is to just switch down to 8-bit colour depth. That will then allow you to run all the way up to 160Hz maximum. If you want to go all the way to 175Hz then you have to switch down to a lower chroma sub-sampling which gives you a limited RGB range and 4:2:2 chroma. This option does have a visual impact to the image, most noticeably with text clarity and colours. You get a bit of coloured fringing in places on text, particularly if it's small and if it's on coloured backgrounds. Some colours look slightly off in place, either too dull or too saturated as well.



Above: photo showing text rendering at 175Hz with forced chroma sub-sampling

This chroma sub-sampling on the 38GL950G we felt led to more noticeable loss in clarity, and some more noticeable colour fringing on text compared with other high-end gaming screens we've tested recently where this is needed - like the Asus ROG Swift PG27UQ and Asus ROG Swift PG35VQ. We certainly wouldn't recommend using 175Hz for day to day office and general usage as the text clarity is impacted. It's still a useable mode for gaming though where these issues are much less apparent. If you don't want to enter the realms of chroma sub-sampling at all, 160Hz is the optimal refresh rate while maintaining a full RGB range. That was our preference with the screen.



Variable Refresh Rates (VRR)

Maximum Refresh Rate 144Hz DisplayPort native

175Hz DisplayPort with Overclock

85Hz HDMI (at native res) Variable Refresh Rate technology Native NVIDIA G-sync with v2 hardware module AMD FreeSync support via DisplayPort adaptive-sync HDMI-VRR for consoles Variable Refresh Rate Range 1 - 175Hz

The screen features a Native G-sync hardware module (v2) with support for HDR input sources, along with the latest DisplayPort 1.4 and HDMI 2.0 interfaces. This of course accounts for variable refresh rate (VRR) support from compatible NVIDIA graphics cards, with certified and thoroughly tested performance levels and criteria. This is one of the reasons why traditional native G-sync remains popular and sought after by gamers for their verified performance and excellent VRR experience..

Unlike all other Native G-sync screens we've tested in the past, this model is the first we've seen that also supports adaptive-sync over DisplayPort! This means that it can be used with AMD FreeSync systems for VRR as well! This was something we announced and covered back in November 2019, with NVIDIA offering adaptive-sync support from future Native G-sync screens via a new firmware. The adaptive-sync range as reported by the AMD control panel is the full 1 - 175Hz, although we believe in practical terms the lowest active refresh rate is 30Hz for G-sync screens and anything below that behaves a bit like LFC on FreeSync screens. Although this tends to work more smoothly than LFC, which is probably why NVIDIA talk about G-sync just supporting the full refresh rate range all the way from 1Hz when they market G-sync. Nevertheless this is a wider range than is supported by adaptive-sync screens and also carries NVIDIA certification and testing for VRR that is associated with the hardware module.

Of other note is the support for HDMI-VRR which will allow support for VRR from compatible games consoles. Also very nice to see included here.

The support for FreeSync and G-sync will be very useful given the significant system demands of running a screen at 3840 x 1600 resolution and up to 175Hz refresh rate. It was of course very good to see it included here. You might also want to read our detailed article about Variable Refresh Rates here.



Detailed Response Times

The response time performance of the 38GL950G was simple, as you could stick with the 'Fast' Response Time mode we felt for all refresh rates, including for VRR and for a fixed 60Hz input sources. The higher refresh rates offered by the screen really help improve motion clarity and reduce perceived blur, making the screen far better for gaming than 60Hz-only models. The support for VRR from both AMD and NVIDIA systems was very welcome and it was great to see this option offered now from a Native G-sync hardware module screen. VRR support is particularly useful given the high demands of this resolution and refresh rate combination.

Recommended Settings

Optimal Refresh Rate 160Hz (for 8-bit and RGB colour) Optimal Overdrive Setting (for above) Fast Optimal Overdrive Setting for 60Hz Fast Optimal Overdrive Setting for VRR Fast



Detailed Measurements at optimal 160Hz, Response Time = Fast

We carried out some further response time measurements at 160Hz and at the optimal 'Fast' response time setting. The average response time was measured at a very impressive 3.7ms G2G - the fastest IPS panel we've ever tested in fact! The fastest measurement was down to 2.4ms while even the slowest was only 5.0ms. Very impressive indeed for this technology. At 160Hz a new frame is sent to the screen every 6.25ms and so response times need to ideally be consistently less than this to keep up. 100% of the pixel transitions were within this window here, so there was no added blurring or smearing because the response times couldn't keep up. There were a few transitions where moderate overshoot started to creep in, most notably when switching between two light grey / white shades. This was not visible in practice though, and we would still rate the overshoot performance as very good here.



Pursuit camera photos of the 'Fast' Response Time mode 160Hz

We also took some photos using a pursuit camera setup to give you an indication of the real perceived motion clarity in this 'Fast' Response Time mode, at 160Hz refresh rate. The motion clarity was excellent here with very low levels of blurring and sharp, crisp moving images.

Detailed Measurements at maximum 175Hz, Response Time = Fast

In case you want to push the screen up to the maximum refresh rates to eke out that small extra bit of frame rate support and perhaps a minor improvement in motion clarity we have also included the detailed measurements at 175Hz. Remember, you need to drop to 4:2:2 chroma sub-sampling to use this mode so there is a drop in image clarity and text rendering in particular. Response times improved ever so slightly here but overall they were pretty similar to at 160Hz. Still 100% of the transitions were within the refresh rate window, even though that now required them to be <5.71ms.



Gaming Comparisons

We have provided a comparison of the display against many other gaming screens we have reviewed in a similar size range and across a range of panel technologies. This table is split by panel technology to make life a bit easier and for quicker comparison.

Overall the response times of the 38GL950G were very impressive. These were the fastest response times we'd measured to date from any IPS panel, beating by quite a way the 27GL950 even which has impressed us when we tested that, and even the recent 240Hz IPS panel of the Acer Nitro XV273 X. All this was achieved with very low levels of overshoot and with a support of up to 175Hz refresh rate too. Response times were reaching in to the "fast TN Film" territory almost. Those high refresh rate TN Film panels can still offer a slightly more snappy experience with slightly better response times in many cases. A jump up to 240Hz can also offer some additional benefits in motion clarity as well but the 175Hz offered here is still very impressive.

We've only tested one 240Hz IPS panel so far which is the Acer Nitro XV273 X. Both that and the LG 38GL950G are incredibly fast IPS screens, and we would probably say the motion clarity and overall performance is very close between the two. On the one hand the Acer has the higher refresh rate which can positively impact motion clarity, but at the same time its response times are a bit slower and not quite fast enough to keep up with that 240Hz. So you get a bit of added smearing as a result of that. The 160/175Hz of the LG is a little slower refresh rate wise, but its response times are better and can fully keep up with the frame rate. Whichever way you look at it, this is a VERY fast screen!



Additional Gaming Features

Aspect Ratio Control - the screen has 2 settings for hardware level aspect ratio control. This includes options for full wide and original. The original mode should be useful if you need to maintain the source aspect ratio if it's anything other than the native 24:10, although there's no direct 1:1 pixel mapping mode offered. Most of this can be achieved from your graphics card anyway if connecting a PC.

Preset Modes - There are a few different preset modes aimed at gaming that can be customised and used if you want. This includes modes for FPS, RTS and two gamer modes.



Black Stabilizer, FPS counter and cross hair - there are settings in the OSD for a familiar FPS counter and cross hair graphic to be added to the screen. There is also a 'Black Stabilizer' feature which alters the gamma in darker parts of the image to help bring out detail. Maybe useful for some darker games.





Lag

Read our detailed article about input lag and the various measurement techniques which are used to evaluate this aspect of a display. The screens tested are split into two measurements which are based on our overall display lag tests and half the average G2G response time, as measured by our oscilloscope. The response time element, part of the lag you can see, 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 of the lag you would feel from the display. We also classify each display as follows: Lag Classification Class 1) Less than 8.33ms - the equivalent to 1 frame lag of a display at 120Hz refresh rate - should be fine for gamers, even at high levels

Class 2) A lag of 8.33 - 16.66ms - the equivalent of one to two frames at a 120Hz refresh rate - moderate lag but should be fine for many gamers. Caution advised for serious gaming

Class 3) A lag of more than 16.66ms - the equivalent of more than 2 frames at a refresh rate of 120Hz - 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) 2.10 Pixel Response Time Element 1.85 Estimated Signal Processing Lag 0.25 Lag Classification 1

Class 1

The 38GL950G has basically no lag. This is like all other Native G-sync screens we've tested where the hardware module is used. That's another benefit of the module which pretty much guarantees no input lag. We measured a total display lag of 2.10ms. With ~1.85ms of that being accounted for by pixel response times we can estimate a signal processing lag of only 0.25ms here. No issue at all of course for even competitive gaming.





Movies and Video

The following summarises the screens performance for videos and movie viewing:

Category Display Specs / Measurements Comments Size 37.5" ultrawide Large for a desktop monitor currently Aspect Ratio 24:10 Some content and devices might not be set up for this wide format, and so you may end up with black bars down the right and left hand sides, particularly for common 16:9 input sources. Resolution 3840 x 1600 Can support native 1080p content but not Ultra HD 4K natively HDCP Yes Suitable for encrypted content Connectivity 1x DisplayPort 1.4

1x HDMI 2.0 Useful additional 1x HDMI input for external Blu-ray players or games consoles. Would have been good to have a second one, but that's limited by the G-sync module currently Cables DisplayPort and HDMI Both provided in the box Ergonomics Tilt and height Decent adjustment range and good smoothness. Stand is sturdy and there's minimal wobble. Would have been useful to have side to side swivel available here though too Coating Light Anti-glare Provides clear, non-grainy image and avoids unwanted reflections of full glossy solutions Brightness range 59 - 458 cd/m2 Good adjustment range offered including a fairly high peak brightness. Flicker free backlight operation with no PWM Contrast 828:1 after calibration Mediocre contrast ratio but it should still be adequate for most content. If you're watching a lot of dark content in a dark room it might be a bit more limited. The pale IPS-glow may also impact you in these conditions somewhat Preset modes None No specific preset mode for movies or video, but you can always set up one of the customisable 'Gamer' preset modes to your liking Response times 3.7ms G2G, very low overshoot at 160Hz 5.1ms G2G, very low overshoot at 60Hz Response times are excellent and very impressive. Very low overshoot as long as you stick to the optimal 'Fast' mode. This includes at 60Hz where response times were still very good. Viewing angles Very good Thanks to the IPS panel technology, suitable for viewing from a wide range of positions. IPS glow on dark content could present a problem from some wider angles especially in darker room conditions Backlight bleed No issues Some slight clouding in the top right corner but no major leakage on our sample Audio Headphone output No integrated speakers on this model but a headphone jack is provided Aspect Ratio Controls Full wide

Original Decent enough options to account for non-native format inputs via the "original" mode which is good. Missing a 1:1 pixel mapping mode PiP / PbP Not available Neither supported on this model





HDR (High Dynamic Range)

HDR Capability Summary HDR Technical Capabilities VESA DisplayHDR Certification level HDR 400 Local Dimming No Certified to the rather meaningless HDR 400 standard which does not require any form of local dimming and so cannot offer improved dynamic range/contrast. There is at least a wide gamut and 10-bit colour depth capability to offer a boost in colour performance Increased dynamic range (contrast) n/a Increased peak brightness 465 cd/m2 Wide DCI-P3 colour gamut 96.5% DCI-P3 10-bit Colour Depth 8-bit + FRC

The screen can accept an HDR10 input signal but lacks any form of backlight local dimming to actually improve the dynamic range in practice. It does support "global dimming" and this can be set via the 'variable backlight' option in the OSD menu. This is basically controlling the whole backlight at once, like a traditional dynamic contrast ratio. It won't help improve the dynamic range without local dimming and we don't really like this feature at all.

It has a peak brightness of >400 cd/m2 so carries the rather meaningless HDR400 certification. When you input an HDR source (like activating HDR in Windows 10) it is detected automatically in the OSD menu. Windows actually looks fine with HDR activated, you at least don't get a massively washed out image. You lose access to the monitor's brightness control so you have to adjust the SDR brightness slider in Windows to a comfortable level but that's no major issue. With the HDR mode activated you lose access to some of the OSD settings for preset modes, brightness, contrast, black stabilizer. But you do retain control over the colour controls which is unusual, and things like the Response Time control.

We activated HDR mode and measured a peak brightness of 465 cd/m2, which was not really any better than the 459 cd/m2 maximum we'd measured in SDR normal mode. The screen does at least have the capability to enhance the colours for HDR content thanks to its wide gamut backlight (96.5% DCI-P3 coverage) and 10-bit colour depth support so there is some benefit offered there for HDR content.

If HDR is particularly important to you then LG do have another 37.5" gaming model coming out but probably not until very late in 2020. The 38GN950 will be the adaptive-sync equivalent (no G-sync hardware module) and so will have slightly different specs, including a lower 160Hz refresh rate max for instance. It is due to have a VESA DisplayHDR 600 certification which will necessitate the use of some kind of local dimming. This will be edge lit and may not have many zones so it remains to be seen whether it will be of much use in practice. It will still be a step up from the lack of any HDR capability offered here though.



Conclusion

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The 38GL950G was a really impressive gaming screen and probably the best IPS gaming panel we've tested to date. The response times were excellent and the fastest we've measured on any IPS panel, keeping up comfortably with even the maximum overclocked 175Hz refresh rate nicely. The high refresh rate helped offer excellent motion clarity and high frame rate support. We liked to stick to 160Hz where you didn't need to use chroma sub-sampling, and the image quality was excellent. The high refresh rates were supported through NVIDIA G-sync for variable refresh rates which is vital on a screen with such a high resolution and refresh rate. Not only that, but this was the first NVIDIA G-sync module screen we've tested which features the new firmware with FreeSync support too - very welcome! Having a Native G-sync module does add to the cost of the screen but offers some decent benefits that are still very sought after by gamers. This includes certified and verified VRR experience across a very wide refresh rate range, no input lag and variable overdrive support. We can forgive the over-the-top 1ms marketing given how fast the screen really is, but we would encourage manufacturers to stick to realistic figures in the future instead of trying to offer silly specs on paper that aren't practical in real use.

The large screen format provides an excellent resolution for other uses too, with a large desktop area to work with, a sharp image and comfortable font size. The slight boost in resolution compared with common 34 - 35" ultrawide screens was not massive, but it was noticeable and was nice in these kind of applications. The default setup of the screen was decent, and there was support for wide colour gamuts and for sRGB emulation if you'd rather. The colour temperature was a little off in default modes but not too major. The wide colour gamut gives a nice visual boost for games and multimedia as well. Like the 27" 27GL850 model the main weakness of this Nano IPS panel is probably the contrast ratio. At 828:1 after calibration it wasn't terrible by any means, but was a bit lower than most new IPS panels which tend to reach around 1000 - 1100:1 nowadays. This seems to be the area sacrificed by LG.Display perhaps to help drive the response times to such a fast level. The panel also offered the familiar all round performance of an IPS panel with great image quality overall, very wide viewing angles and a stable image. There was the usual IPS-glow on darker content from an angle but no different to most IPS panels out there.

Now on to the most polarising topic - the price. There's no denying that the 38GL950G is a very expensive screen. At the time of writing this review (dated at the top of the page) it is currently available in the US for $1,767 USD from Amazon.com. It's available to pre-order in the UK and stock is expected to appear in the near future, but at a price currently of £1,799 GBP from Overclockers.co.uk. This means that it's going to be more money than many people will want to spend on a desktop display. It's not intended to be a mass market product, and is more of a lower volume flagship offering. Some people may want to hang on for the 38GN950 model in case that's much cheaper, but at the moment it remains to be seen what price it will retail for, how it will perform without the Native G-sync hardware module being used and whether some of the features like HDR 600, that seem positive on paper, will make much practical difference. We expect that screen to be a long way off being released as well, so you could well be waiting another year for it to be readily available anyway.

The 38GL950G is excellent, and if you do have the money and inclination to consider it, then we don't think you'll be disappointed.