Introduction

We have with us now the new 32GK850G display from LG. It's a 31.5" sized screen with a VA technology panel and 2560 x 1440 resolution aimed at the gaming market. Unlike a lot of modern gaming screens of this size, the 32GK850G is a flat format instead of curved. It packs a lot of high end specs and features for gaming including a 5ms G2G response time, 144Hz native refresh rate, overclocking feature to boost the refresh rate up to 165Hz and support for NVIDIA G-sync variable refresh rate technology. There's also some added gaming extras in the OSD menu to enhance your experience, and some design extras like the 'Sphere lighting' system.

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Specifications and Features

The following table gives detailed information about the specs of the screen as advertised:

The 32GK850G offers typical connectivity for a modern G-sync screen with 1x DisplayPort 1.2 and 1x HDMI 1.4 offered for video connections, and an additional 2 port USB 3.0 hub, with the ports located on the back of the screen and both supporting fast charging. The screen has an external power supply and comes packaged with the power cable and brick you need. A headphone output is also provided.

Below is a summary of the features and connections of the screen:

Power Consumption

In terms of power consumption the manufacturer lists normal usage of 55W, and <0.5W in standby. We carried out our normal tests to establish its power consumption ourselves.

Out of the box the screen used 52.6W at the default 100% brightness setting. Once calibrated the screen reached 30.7W consumption, and in standby it used only 0.5W. We have plotted these results below compared with other screens we have tested. The consumption (comparing the calibrated states) is pretty similar to most screens in this size range as you might expect.

Panel and Backlighting

Panel Part and Colour Depth

The LG 32GK850G features an AU Optronics M315DV01 AMVA (VA-type) technology panel which is capable of producing 16.7 million colours. This is achieved through an 8-bit colour depth. The service menu for this screen lists the panel as "AUO_M315DVR01_LGE_BL". This looks to be a new AUO panel since the two current M315DVR01.0 and 1.1 panels are curved format, and this is a flat screen. Having dismantled the screen as well we were presented with an unexpected label detailing an LG Electronics LGM315UK6-VCA1 part number. This is the LG Electronics backlight unit paired with the AU Optronics AMVA panel.

Screen Coating

The screen coating is a light anti-glare (AG) like other modern VA panels, but it is not semi-glossy like some older VA generations tended to be. It retains its anti-glare properties to avoid too many unwanted reflections of a full glossy coating, but does not produce an too grainy or dirty an image that some thicker AG coatings can. There are no visible cross-hatching patterns on the coating.

Backlight Type and Colour Gamut

The screen uses a standard gamut W-LED backlight unit as most screens today do. This offers a normal sRGB colour space, equating to around 72% NTSC coverage. There is no support for any wider colour spaces such as Adobe RGB or DCI-P3 on this model. If you want to read more about colour spaces and gamut then please have a read of our detailed article.

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 previously very 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 = 1 horizontal grid = 5ms

 

Contrast Stability and Brightness

At the top end the maximum luminance reached a high 328 cd/m² which was a little lower than the specified maximum brightness of 350 cd/m² from the manufacturer, although on the other hand this was higher than the minimum figure of 280 d/m² they also quote. There was a good 260 cd/m² adjustment range in total, so at the minimum setting you could reach down to a fairly low luminance of 68 cd/m². This should be low enough for most people including those wanting to work in darkened room conditions with low ambient light. A setting of 19 in the OSD menu should return you a luminance of around 120 cd/m² at default settings. It should be noted that the brightness regulation is controlled without the need for Pulse Width Modulation for all brightness settings so the screen is flicker free.

    

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 is a linear relationship as you can see.

The average contrast ratio of the screen was excellent thanks to the VA technology panel, measured at 3193:1 before calibration. We have not provided the usual graph showing contrast stability, as with such low black depths, rounding errors come in to play at two decimal places and this skews the visual representation.

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.

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 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.

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/m², 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:

Initially out of the box the screen was set in the 'gamer 1' mode with a setting of 'mode 2' for the gamma, and 'custom' for the color temp modes. We will test the impact of those settings in a moment for completeness. The display was also set with a very high 100% brightness which was far too bright and uncomfortable to use. You will definitely need to turn that down. The colours felt decent and well balanced, if perhaps a little warm.

We went ahead and measured the default state with the i1 Pro 2. The CIE diagram on the left of the image confirms that the monitors colour gamut (black triangle) matches the sRGB colour space reference (orange triangle) very closely. We measured using ChromaPure software a 102.1% sRGB gamut coverage which corresponds to 75.3% of the DCI-P3 reference and 54.0% of the Rec.2020 reference. This screen is only designed to be a standard sRGB display, so this was expected. It was good to see a full 100% sRGB coverage with no under-coverage, and no real over-coverage anywhere.

Default gamma was recorded at 2.3 average, with a moderate 7% deviance from the target. White point was measured at a slightly too warm 5933k which left it a moderate 9% out from the 6500k we'd ideally want for desktop use. There are a range of other colour temp presets available in the menu along with this 'custom' mode where you have access to the individual RGB channels for the calibration process.

Luminance was recorded at a very bright 347 cd/m² which is far too high for prolonged general use, you will need to turn that down. The screen was set at a default 100% brightness in the OSD menu but that is easy to change of course to reach a more comfortable setting without impacting any other aspect of the setup. The black depth was 0.106 cd/m² at this default brightness setting, giving us a very strong static contrast ratio of 3276:1. Colour accuracy was very good out of the box with an average dE of 2.0 and a maximum of only 2.9. Testing the screen with colour gradients showed smooth gradients with only minor gradation evident in the darker tones. There was no sign of any colour banding which was good news.

We also tested the few gamma and colour temperature modes at default screen settings:

The gamma mode 1 seemed to be a little closer to our target of 2.2 with only a 3% deviance, so that seemed to be the optimum starting point when it came to gamma. If you want it a little higher, then mode 2 offers you that.

The 'medium' colour temp mode was closest to our 6500k target out of the box, although the 'custom' mode gives more flexibility as you can then change the individual RGB channels yourself, and achieve a custom white point. We will stick to the custom mode for our calibration in a moment, and change the RGB channels to correct that white point to as close to 6500k as possible.

Calibration

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 colorimeter was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

We first of all switched to the gamma mode 1 which we had found to be closest to our 2.2 target out of the box and would therefore require less correction. We also stuck with the 'custom' color temp mode which gives you access to adjust the RGB channels individually. We adjusted the RGB channels and brightness setting as shown in the table above as part of the guided calibration process. 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.

Average gamma was measured at 2.2 average (0% deviance) which fixed the 7% deviance we'd seen out of the box at default settings. The moderate 9% white point deviance had now been corrected bringing the measured white point to 6494k. Luminance had been improved thanks to the adjustment to the brightness control and was now being measured at a far more comfortable 120 cd/m². This left us a black depth of 0.04 cd/m² and a static contrast ratio of 2950:1 which was excellent thanks to the VA panel technology. Colour accuracy of the resulting profile was excellent too, with dE average of 0.4 and maximum of 1.1. LaCie would consider colour fidelity to be excellent. Testing the screen with various colour gradients showed mostly smooth transitions with only some minor gradation in darker tones, and a little banding introduced in the darker tones due to the gamma correction. 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. 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.

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 out of the box was moderate. The gamma curve was a little way off our target with a 7% deviance, but this could be corrected within 3% of the target by switching to mode 1 before any calibration was needed. White point was a bit off (9%) and a bit too warm but not too hard to adjust through RGB changes, or maybe even moving to the 'normal' color temp mode. The screen did show a very high static contrast ratio thanks to the VA panel which was pleasing and there was also a low dE of only 2.0 average out of the box which was great.

Where the 32GK850G did very well is in black depth and contrast ratio, thanks to the use of a VA technology panel. we measured a calibrated contrast ratio of 2950:1, the highest out of the models shown here. Many other modern VA panels have taken a step back and only offer contrast ratios of around 2000:1, but it was nice to see this pushed back up to around 3000:1 on the 32GK850G. This exceeds anything currently possible from TN Film or IPS panels by quite a long way, which reach around 1200 - 1400:1 at best, and normally more like 1000:1.

Viewing Angles

Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the screen were a little better than many other VA technology panels we've seen in recent times. Contrast shifts became evident from a side angle past about 30� but were not too distracting. Vertically they were more pronounced, with the image becoming more washed out from above and below. They were slightly better than the Samsung C32HG70 we tested recently (Samsung SVA panel), which showed a little more colour tone shift. They were noticeably better than some other VA screens we've tested which showed much more noticeable contrast shift and washing out of the image. For instance the Philip 349X7FJEW (Samsung SVA) and AOC AGON AG352UCG (AU Optronics AMVA). A pretty decent job here for a VA panel, we were pleased.

These viewing angles were not as wide as you would experience from an IPS panel so that is generally the preferred option for colour critical work. Obviously this is aimed at gaming though, and for those uses it is perfectly fine and offers obvious improvements over common TN Film based gaming screens. It should also not be forgotten that this VA panel offers much higher static contrast ratios than can be achieved from TN Film or IPS.

The VA panel used has actually done a good job of reducing a common VA viewing angle issue, which is the off-centre contrast shift or "black crush" as it's sometimes called. On most VA panels when viewing a very dark grey font for example on a black background, the font disappears when viewed head on, but gets lighter as you move slightly to the side. Lighter greys and other colours will appear a little darker from head on than they will from a side angle, but you may well find you lose some detail as a result. This can be particularly problematic in dark images and where grey tone is important. It is this issue that has led to many graphics professionals and colour enthusiasts choosing IPS panels instead, and the manufacturers have been quick to incorporate this alternative panel technology in their screens. Many people don't even notice this or find it an issue but it's something to be aware of on most VA panels. On this screen, the off-centre contrast shift is reduced somewhat, and you do not lose much contrast when viewed head on like on many other VA screens.

Above: View of an all black screen from the side. Click for larger version

On a black image viewed from an angle, the image remains consistent, and does not introduce the obvious pale or purple glow that IPS-type panels do. This is a strength of VA panels and a big reason why some people prefer them over IPS. The performance here was better than we'd seen from other recent VA panels in fact, which was great news. The Samsung C32HG70 and Philip 349X7FJEW for instance showed some pale glow from an angle on dark content, not as noticeable as on IPS but certainly more than we saw here on the 32GK850G. Another good job with black-content viewing angles.

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 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/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

Uniformity of the screen was moderate on this sample. The upper corners showed a drop in luminance by 20% in the most extreme measurements, down to 100 cd/m² and the upper edge was a little darker than the lower and middle regions of the panel. Around 60% of the screen was within a 10% deviance of the centrally calibrated point. It's not a screen designed for any colour critical work so these variations are not likely to cause any problems. You shouldn't notice anything for the intended uses of gaming for instance.

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version

We also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. The camera showed there was no noticeable backlight bleed or clouding on this sample which was great news. The image was dark and consistent thanks to the VA panel. In fact if you're viewing this on a non-VA screen, you may have trouble distinguishing the black screen content from the black borders of the panel.

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/m² 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.

General and Office Applications

The screen features a 2560 x 1440 resolution which is fairly common nowadays, but the difference here is that it is on a slightly larger screen size than normal. The 32GK850G is 31.5" in size, making it 4.5" larger diagonally than the typical 27" models featuring this resolution. The larger screen size is designed to provide more immersion for multimedia and games, giving a bigger screen to look at, especially useful if you want to view it from a little further back than a typical PC viewing position as is sometimes the case for gaming. This resolution on the larger screen size looks fine. You will see slightly larger font sizes with the 0.272mm pixel pitch here and so for office work it doesn't look quite as sharp as on a 27" model. Some people may even prefer this slightly larger font though for more comfortable reading, and it's certainly not too big we didn't think for a screen this size. It also avoids the need to worry about any Operating System or software scaling which you would have to contend with on 3840 x 2160 Ultra HD resolution displays of this size. The text is ever slightly blurred we felt, although there's no sharpness control in the OSD to adjust this. It's very minimal, and just looks slightly softer than we are used to from say a 27" 1440p screen. This sometimes resulted in focusing problems with text. The flat screen format might be preferable to some users, although we felt that we'd gotten used to using curved format displays at these larger sizes, and so it felt the edges of the screen were a little far away from you here on a flat format. That's all down to user-preference of course.

The light AG coating of the panel is welcome, and much better than the grainy and 'dirty' appearance of some other AG coatings on some displays. The wide viewing angles provided helps minimize on-screen colour shift when viewed from different angles, with no noticeable glow on dark content and even a low level of off-centre contrast shift/black crush from this panel. The default setup of the screen offered a reasonable setup for gaming needs, but was a little off for more general uses. The  gamma curve was a little high and white point a little too warm, but on the other hand the panel did have a strong contrast ratio and low dE.

The brightness adjustment range of the screen was very good, with the ability to offer a luminance between 328 and 68 cd/m². A setting of 19 in the OSD brightness control should return you a luminance close to 120 cd/m² out of the box. On a positive note, the brightness regulation is controlled without the need for the use of 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 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 cool even during prolonged use. There is a 'Reader' preset mode available in the menu which creates a much warmer setup than our calibrated 6500k mode. Maybe useful at night time for a warmer image when viewing a lot of white-background content.

The screen offers 2x USB 3.0 ports (with charging capabilities also) which is very handy, although they are on the back of the screen with the input connections so not really that easy access. There are no integrated stereo speakers on this model, but there is an audio input and headphone output. There aren't any other extras like card readers or ambient light sensors offered though which can sometimes be useful in office environments. The stand offers a wide range of adjustments which is great news, allowing you to obtain comfortable viewing positions.

 
Responsiveness and Gaming

The 32GK850G is rated by LG as having a 5ms G2G response time. The screen uses overdrive / response time compensation (RTC) technology to boost pixel transitions across grey to grey changes as with nearly all modern displays. There is a user control in the OSD menu for the overdrive under the 'Response Time' setting with 4 options available - Off, Normal, Fast and Faster. The part being used is an AU Optronics M315DVR01 AMVA technology panel.  Have a read about response time in our specs section if you need additional information about this measurement.

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.

We carried out some initial response time measurements in each of the overdrive settings, along with some visual tests. We didn't bother testing the 'Off' mode, as there's no reason to use it considering there's no overshoot visible in the higher modes. The response times remained consistent regardless of the refresh rate, from 60Hz all the way up to the overclocked 165Hz.

As you can see above, the response times improved a little each time you increased the 'Response Time' control. None of the modes showed any overshoot at all in these measurements which was excellent news, so you don't need to worry about annoying dark or pale halos caused by a poorly configured overdrive impulse. That normally becomes a major problem when you push response time settings up to the maximum, but LG have been more conservative with the RTC impulse here. There was a small improvement in pixel response times with each increase in the setting, but not by a massive amount. The 'Faster' mode seemed to deliver the optimal performance, with an average G2G of 10.1ms measured. This was skewed a little by some slower black transitions, which is pretty common from VA technology panels. The changes from black to dark and medium grey (0>50 and 0>150) were much slower than the rest of the pixel transitions and dragged the overall average down as a result. If you ignore those very slow transitions from black, the 'Faster' mode actually averaged 6.8ms G2G which is much better.

Pursuit camera photos to represent real perceived motion blur at various settings

In practice you can see the evidence of these slower dark transitions as it results in some black smearing on moving content, where the pixels are slow to change from black shades to grey. We have provided a visual representation of this above from the Blurbusters.com testufo images using a pursuit camera. This is designed to capture motion blur as the human eye would perceive it and so is a decent representation of what you would see in person.

As we have already said, there was no overshoot evident, so no annoying halos introduced because of that. You can see the dark trailing evident behind the moving UFO, particularly on a dark background where the black outline of the UFO is changing to a dark shade. This gets slightly less as you increase the response time control but it's still there even at the maximum 'faster' setting. It's on the lighter backgrounds where you can pick out some improvements in response times. There is a bit more dark smearing at the 'normal' setting in the middle and bottom UFO images, and this is largely eliminated by the time you reach the 'faster' mode. Most of those transitions you see measured in the middle of the tables above have been sped up, and so that's where this improvement comes from.

Unfortunately there is no motion blur reduction backlight provided on this model, which is a bit of a shame considering it is a G-sync screen. Usually G-sync screens will make use of NVIDIA's Ultra Low Motion Blur (ULMB) technology which is incorporated in to the G-sync chip, and offer a strobed backlight feature. This can really help improve perceived motion blur for gaming and make moving images sharper and easier to track. For some reason despite G-sync being used, and there being a high refresh rate, ULMB is not offered on this display.
 

Refresh Rate, G-sync and Overclocking

This screen supports high refresh rates up to 144Hz natively, and 165Hz with an overclocking feature. High refresh rates bring about noticeable and obvious benefits in fast moving content and put these screens ahead of common 60Hz models when it comes to fast gaming. You get support for higher frame rates for a start, which is important for competitive gaming. Because of the way LCD screens operate, refresh rate also has a direct relation to how the human eye perceives motion blur. The higher the refresh rate, the less motion blur you will see from the screen. So the ability to support beyond 60Hz is very welcome when it comes to improving the gaming experience.

One thing to keep in mind also is whether the pixel response times are fast enough to keep up with the frame rate demands of the high refresh rate. To deliver 144Hz, a new frame is sent to the screen every 6.94ms, which means that response times need to be consistently under this to keep up. If they're not, then you end up with some added smearing on fast moving content. For the 165Hz overclocked refresh rate you need response times to be <6.06ms to keep up (1000 ms / 165 Hz = 6.06ms). On the 32GK850G the response times (even if we ignore the few slow black transitions for now) were not quite fast enough to keep up with 144Hz or 165Hz refresh rates, and you get a little added smearing in practice if you use the screen at those settings. We felt 120Hz (needing <8.33ms) was a better balance and provided the optimal experience.

Above are some pursuit camera tests running the screen in the optimal 'Faster' response time mode, at both 120Hz and 165Hz. You can see the dark trailing evident at both refresh rates behind the moving UFO, particularly on a dark background where the black outline of the UFO is changing to a dark shade. It's on dark content where the black smearing becomes most noticeable. You can see that a little bit more smearing and blurring is visible at the max 165Hz refresh rate, and that's because the pixel response times have trouble keeping up with the frame rate of the screen. You start to get more noticeable smearing, especially with blacks. So despite the added refresh rate helping to reduce perceived motion blur in theory, the performance is being limited by the response times of the pixels themselves. We would recommend sticking with 120Hz for optimal performance, although 120 - 165Hz is still useable and doesn't look terrible. If you're using G-sync for instance and wanted to use the full range up to 144Hz or 165Hz, it is still very usable, and you may not be pushing frame rates that high regularly anyway.

The screen supports NVIDIA G-sync for variable refresh rates, with a nice wide range of 30 - 144Hz supported natively, and the ability to support 30 - 165Hz when the overclocking feature is used. This helps remove tearing and stuttering when you have varying frame rates in gaming, without adding the lag that traditional Vsync would introduce. The benefits of G-sync (and AMD FreeSync) are well documented so we won't go in to those here, but it's a big benefit to have that support when it comes to gaming. To power a screen at 2560 x 1440 resolution and 165Hz refresh rate will need a high end system and graphics card, so the presence of G-sync to support dipping frame rates and less powerful systems is very useful.

The overclocking feature is enabled within the OSD menu with a simple on/off setting. The screen then reboots, and you should be able to choose 165Hz easily from within Windows or your graphics card settings. We would recommend using the provided DisplayPort cable if you have any issues with compatibility. We tested the screen at 165Hz and found no dropping of frames from our NVIDIA GTX 970 graphics card which was excellent news.
 

Detailed Response Time Measurements
Response Time mode = Faster

Having settled on the 'faster' response time mode in our earlier measurements and visual tests we carried out a more thorough set of measurements across a wider range of pixel transitions. The average G2G figure was measured at 8.3ms which was good for a VA panel. In fact it would have been even better at about 6.4ms G2G if we didn't have those few particularly slow changes from black > grey. As is common on most VA panels, there are some slow changes from black, which results in practice with some dark smearing on moving content. It's less noticeable at this maximum 'faster' response time setting but it's still there sadly. This mode has at least eliminated some of the slow middle G2G transitions you get in the 'fast' and 'normal' response time modes which is good news. In the best case the response time actually reached down to 2.8ms G2G which was impressive. The quoted 5ms figure is actually conservative from LG if you want to consider the best case measurement.

There was very little overshoot at all. Some moderate overshoot started to creep in on a couple of transitions, those between similar light grey and white shades. It was not particularly high and we didn't really notice any issues with it in practice to be honest. If you find it troublesome at all, you can always drop down to the 'fast' setting. As a reminder, we felt that 120Hz was the optimal refresh rate on this screen before additional smearing started to be introduced for settings higher than that.
 

Gaming Comparisons

We have provided a comparison of the LG 32GK850G against many other screens that we have tested. The screen performed better than most other VA technology displays listed here. With an average G2G of 8.3ms, it was faster than the recent competing Samsung C32HG70 model, which measured in at 13ms G2G average but also showed a lot more slow transitions from dark to light shades. There was less noticeable dark smearing as a result on the LG. It was a little better for gaming than the Asus ROG Strix XG35VQ overall as well, which struggled even more with transitions from black to dark grey, and also showed some high levels of overshoot in practice.

Being a VA panel it still struggled with some of those darker transitions and so black smearing was still apparent on moving content in certain situations. We feel that the high refresh rate IPS panels such as the Asus ROG Swift PG279Q (5.0ms G2G average, 144Hz) and Dell Alienware AW3418DW (6.9ms G2G, 120Hz) for instance offered a smoother experience without that dark smearing becoming a problem. Of course you are then having to live with a much lower contrast ratio and put up with the pale "IPS glow" from that technology, so it depends what is important to you. For a VA panel, the 32GK850G was a good option we felt when it came to gaming.

Additional Gaming Features

• Aspect Ratio Control - the screen has 3 options for hardware level aspect ratio control options, with settings for 'full wide', 'original' and 1:1 pixel mapping offered. That's useful as there's settings to match the input aspect if it is different to the native 16:9 of this screen.

• Preset Modes - There are a series of preset modes available in the menu for different gaming uses, including FPS and RTS games. Some of the settings are locked in the FPS and RTS preset modes including black stabilizer (which varies in each mode), response time (which is always locked to 'faster'), gamma, colour temperature and the RGB channels. You can still control things like the brightness of the screen and the overclock feature in all modes. If you want more flexibility to set the screen up to your liking, there are also 2 fully customisable 'gamer' preset modes which is useful. One gripe is that the preset modes do not offer much flexibility. They do have preset levels for black stabilizer and response time, and you can change the brightness/contrast setting in each. However, this brightness/contrast adjustment cannot be saved for each preset mode individually, they apply universally across all of them.
   

• Black stabilizer - this setting allows you to adjust the gamma curve to bring out more detail in darker content. The VA panel offers a great static contrast ratio anyway but this might be a useful setting to play with depending on your gaming environment and the content you're viewing.

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 8ms / 1 frame lag at 120Hz - should be fine for gamers, even at high levels

• Class 2) A lag of 8 - 16ms / One to two frames at 120Hz - moderate lag but should be fine for many gamers. Caution advised for serious gaming

• Class 3) A lag of more than 16ms / more than 2 frames at 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.

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.

We measured a total display lag of only 6.40ms. With approximately 4.15ms of that accounted for by pixel response times we had an estimated signal processing of just 2.25ms, which was next to nothing. This is in keeping with other G-sync screens we have tested, as the absence of an additional scaler (and presence of the G-sync module) allows for extremely low lag.

Movies and Video

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

Conclusion

The 32GK850G offered a very good option for gamers we felt in the VA technology market. There's a lot of different gaming screens out there based on a mixture of TN Film, VA and IPS technologies as you probably know, with VA proving a popular choice for many at the moment. This technology delivers very high contrast ratios and deep blacks which far surpass what can be achieved from TN Film/IPS. We were impressed with the ~3000:1 contrast ratio here compared with many other modern VA panels which have been around the 2000:1 mark instead. While not offering quite as wide viewing angles as IPS is capable of, the VA panel is however free of the annoying pale IPS-glow on dark content which many people dislike from that technology, and combined with the high contrast ratio that helps provide great performance in darker gaming and multimedia uses. The viewing angles of the 32GK850G were a bit better than many other VA panels we've seen as well, showing less contrast and colour shift and even a reduction in the off-centre black crush which impacts these kind of panels.

In non-gaming areas we liked the screen design and the Sphere lighting was a nice added touch. There was a decent range of features and settings available as well, although limited connectivity because of the use of NVIDIA G-sync. The default setup of the screen was a little off in some areas and we felt like the menu options and preset modes were perhaps too weighted towards gaming, without any modes for more general use. Perhaps not a surprise given the target market and a minor criticism as it's still easy to adjust one of the customisable modes to achieve a decent every day setup.

When it comes to gaming we felt the 32GK850G offered a good performance and is one of the better VA panels we've tested. The 31.5" screen size added a little extra immersion compared with more common 24 - 27" sized screen although we think we prefer curved format when you get to this kind of size having used a fair few now. The response times were generally good, with no real overshoot to speak of which was great news. Although the screen was unfortunately still affected by a few slow transitions from black to grey, resulting in some additional black smearing in practice. This was not as noticeable as some other VA panels, but it was still there. It was great to see the boosted high refresh rates here as well, although we felt 120Hz was probably the optimal upper limit given the response times. The ability to natively support up to 144Hz and even 165Hz with the overclock (which worked very well without dropping frames) might be useful to some, or to provide a wider range in which G-sync can operate and vary the refresh rate. G-sync as ever provided smooth performance and will help cope with varying refresh rates and system builds. Input lag was also incredibly low thanks to the G-sync module. It was just a shame that ULMB was not included for blur reduction, despite the G-sync usage and high refresh rate. All in all it was a very good gaming screen if you're after a VA panel with strong contrast and good all-round performance.

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