ViewSonic Elite XG270QG

Introduction

Back in August 2019 we reviewed the LG 27GL850, which has been one of the most popular monitors of recent times. This 27" gaming monitor was the first to feature LG.Display's new Nano IPS panel, offering a 2560 x 1440 resolution, 1ms G2G response time spec, high 144Hz refresh rate and a wide DCI-P3 colour gamut. The 27GL850 is supported by VESA adaptive-sync for variable refresh rates from both NVIDIA and AMD systems, and performed very well overall. We have with us now ViewSonic's competing Elite XG270QG display. This is based on the same Nano IPS panel as the LG, but has several key differences. The XG270QG is a Native G-sync screen, featuring NVIDIA's hardware G-sync module and offering some additional gaming benefits that this technology provides. This includes allowing for a slightly increased refresh rate through an overclocking function, with the XG270QG supporting up to 165Hz max. There is also an added ULMB blur reduction mode which was not offered on the LG 27GL850, and some additional RGB lighting which is often popular with gamers. While a Native G-sync module usually means you can only use VRR from an NVIDIA graphics card, the XG270QG is actually one of the models to feature the latest firmware allowing for the screen to also work from AMD FreeSync graphics cards when using DisplayPort. Note that HDMI-VRR is not supported though.

Specifications and Features

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

The XG270QG offers a somewhat limited range of modern connectivity with 1x DisplayPort 1.2a and 1 x HDMI 1.4 offered for video connections. This is restricted by the user of the G-sync v1 module. These are located on the back of the screen along with a headphone output and 3x USB downstream ports. For PC connectivity the DisplayPort is the most common option, with HDMI being available then for connecting external games consoles or Blu-ray players potentially. The screen has a small external power supply brick and the screen also comes packaged with the power cable that you need.

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

Power Consumption

We have plotted these results below compared with other screens we have tested. The consumption (comparing the calibrated states) is comparable to most of the other 27" sized screens we've tested as you might expect. The larger screens tend to have additional power usage as does the 27" Asus ROG Swift PG27UQ with it's FALD backlight.

Panel and Backlighting

Panel		Backlight
Panel Manufacturer	LG.Display	Backlighting Type	LED
Panel Technology	Nano IPS	Colour space	Wide gamut
Panel Part	LM270WQA	sRGB coverage spec	133%
Screen Coating	Light anti-glare	DCI-P3 spec	98%
Colour Palette	16.7 million	Adobe RGB coverage spec	not listed
Colour depth	8-bit	Flicker free verified

Note that although the ViewSonic advertised spec lists 1.07b colour depth, and the panel being used is 8-bit+FRC, it is not possible to set the screen to anything above 8-bit as this is a limitation of the Native G-sync hardware module.

Backlight dimming at calibrated brightness setting (no PWM)

Above: backlight operation showing constant Direct Current voltage instead of PWM. Measured at calibrated brightness level

Brightness and Contrast

At the full brightness setting in the OSD the maximum luminance reached a very high 434 cd/m² which was a little higher even than the 400 cd/m² max brightness spec from the manufacturer. There was a pretty decent 347 cd/m² adjustment range in total, so at the minimum setting you could reach down to a luminance of 87 cd/m². This doesn't afford you a super-low luminance option for working in darkened room conditions with low ambient light however so be a little wary if that is a specific requirement for you. A setting of 9 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 measured at 961:1 out of the box which was about standard for an IPS-type panel. It remained pretty stable across the brightness adjustment range as you can see above. Note that the contrast ratio is impacted by calibration which you can read about in a moment.

 

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 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.

Targets for these tests are as follows:

• 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

• 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.

• 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 (static) - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

• 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.

Default Performance and Setup

Default settings of the screen were as follows:

Default gamma was recorded at 2.3 average with a minor 4% deviance from the target which was pleasing. There are some gamma modes available in the OSD menu but the default 2.2 mode was closest to the 2.2 target here anyway. White point was measured at 5632k, being a fair bit too warm with a 13% deviance which will ideally need correcting. This was in the default 'native' colour temperature mode by the way.

Luminance at the default 100% brightness level was recorded at 433 cd/m² which is a far too high for prolonged general use, you will need to turn that down. The black depth was 0.46 cd/m² at this default brightness setting, giving us a fairly typical, and decent enough static contrast ratio for an IPS-type panel of 943:1. Colour accuracy measurements should be ignored here really as they are comparing the produced wider gamut display colours against an sRGB reference which will always lead to errors. There was no sign of any colour banding when testing gradients which was good news, and some typical gradation in darker tones evident.

Optimal Settings Pre-Calibration

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.
 

This has helped correct the white point to approximately 6500k and reduce the brightness to a much more comfortable level. The contrast ratio has reduced a fair amount due to the RGB corrections, now measured at 812:1. Perhaps not unsurprising as we had seen a very similar contrast ratio from the LG 27GL850 after making OSD corrections and carrying out a calibration (848:1). Further calibration and profiling below will help improve things even further.

 

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

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.

The already pretty decent default gamma curve had been improved to 2.2 average, correcting the 4% deviance we'd seen out of the box. The white point was also now improved to 6551k which was great news, leaving only a minor 1% deviance from our target. The brightness control adjustment had reduced the luminance to a comfortable level now, but compared with the out of the box setup, the contrast ratio had taken a hit. This was now measured at 811:1 as we'd had to adjust the RGB channels to correct the white point. Colour accuracy of the resulting profile was very good, with dE average of 0.5 and maximum of 0.9. LaCie would consider colour fidelity to be very good overall. Gradients remained mostly smooth with some minor banding introduced in mid-dark shades due to the profiling and gamma corrections.

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.

Setup 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 overall. The gamma curve was thankfully pretty decent with only a small deviance, but white point was too warm. This is at least pretty easy to correct from the OSD controls. While we did have a reasonable default contrast ratio out of the box at 943:1, by the time you have corrected the white point and calibrated the screen this has dropped to a fairly low 811:1. This isn't terrible, and it's the same thing we say from the LG 27GL850 which uses the same Nano IPS panel. We also saw the same kind of thing from the LG 38GL950G which has a larger 37.5" ultrawide Nano IPS panel. The XG270QG has a wide colour gamut which offers vivid and bright colours, but unfortunately on this model there is no sRGB emulation mode available.
 

The contrast ratio was fairly poor for a modern IPS panel and was measured at 811:1 after calibration. This was lower than a lot of modern IPS panels which can reach up to around 1100 - 1300:1 in some case. And of course none of these can live up to the much higher contrast ratios of VA-type panels which are more like 2000 - 3000:1 commonly.

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Viewing Angles

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

Viewing angles of the screen were very good as you would expect from an IPS-type panel. 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.

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

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. It appeared a little more white in colour when viewed from the right hand side but in practice the above photo is fairly typical. 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 may see this glow as your eyes look towards the edges of the screen. The level of glow on this panel was the same as the LG 27GL850 which is not surprising as it uses the same panel.

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 may see this glow as your eyes look towards the edges of the screen depending on your viewing position. It will also be more noticeable in darker ambient light conditions and if you're viewing a lot of dark content. Some people may find this problematic if they are playing a lot of darker games or watching darker movies. In normal day to day uses 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 keep in mind, the effect reduces as you do not have such an extreme angle from your eye position to the screen edges.

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

Luminance uniformity of the screen was moderate on our sample, with 63% of the screen within a 10% deviance of the centrally calibrated area. Towards the four corners showed the most significant variation, dropping down to 94 cd/m² in the most extreme example (-28% deviance). 

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. There was some reasonably noticeable leakage from the top and bottom left hand corners on our sample. This was hard to see during normal usage though of course, but might show on darker content or in extreme tests like this. Results will vary from sample to sample keep in mind.

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

This screen features a 2560 x 1440 WQHD resolution, a significant step up from the wide range of 1920 x 1080 screens on the market and a comfortable resolution for this size screen we feel. These higher resolution 27" models offer a tighter pixel pitch of 0.233mm which results in a smaller text size than common 24" 1080p screens, although it is still a nice and comfortable size. We are very used to working with 27" 1440p screens all the time and find them very comfortable and a significant upgrade over 1080 / 1200p models. Some users may find the small text a little too small to read comfortably, and we'd advise caution if you are coming from a smaller screen for instance where the pixel pitch and text are normally larger. The extra screen size takes some getting used to over a few days as there really is a lot of room to work with but once you do, it's excellent. For those wanting a high resolution for CAD, design, photo work etc, this is a really good option. The image was very sharp and crisp and text was very clear. With its WQHD display, you enjoy 77% more desktop space than a full HD screen to spread out your windows and palettes.

The light AG coating of the IPS technology panel is certainly welcome, and much better than the older grainy and 'dirty' appearance of older IPS AG coatings - although it's been many years since those were used. The coating is also a little lighter than most TN Film panels which have a 'medium' grainy appearance.  The wide viewing angles provided by this panel technology on both horizontal and vertical planes, helps minimize on-screen colour shift when viewed from different angles.

The screen always operates with a wide gamut offering 133% sRGB coverage. This is well suited to gaming, multimedia and HDR content producing brighter and more vivid colours but if you were looking to work specifically with sRGB content for photo work or other content, it might present a problem. There's no sRGB emulation mode offered by this screen either so you are stuck with the full wide gamut at all times. There is a good gamma curve setup to this mode, although the colour temperature is a bit warm. That's easy to adjust using either our recommended RGB settings or using the various colour temp modes available in the OSD menu if you need.

The brightness range of the screen was good, with the ability to offer a luminance between 434 and 87 cd/m². This should mean the screen is useable in a wide variety of ambient light conditions, including darkened rooms. Although the minimum adjustment is not super-low on this model. A setting of ~9 in the OSD brightness control should return you a luminance close to 120 cd/m² 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.

Spectral distribution graph showing calibrated mode at 6500k

Spectral distribution graph showing Blue Light Filter mode set to 100 (maximum)

There are some blue light filter settings available in the OSD menu. They only seem to be available in some of the colour temp modes though including the default 'native', but not in the 'user color' mode. There is a slider for settings from 0 - 100 which progressively make the image warmer, reducing the blue light output. At the maximum 100 level the colour temperature was quite a lot warmer at around 3900k. 

There are 3x USB ports provided on this screen, all on the back so they aren't particularly easy access. There are 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 an added headphone hook on the left hand side that might be useful. There is a decent range of ergonomic adjustments from the stand with tilt, height, swivel and rotate offered. There is also VESA 100mm mounting capabilities for those who want to mount the screen instead.

 
Responsiveness and Gaming

Panel Manufacturer and Technology	LG.Display Nano IPS
Panel Part	LM270WQA
Quoted G2G Response Time	1ms G2G
Quoted MPRT Response Time	n/a
Overdrive Used
Variable Overdrive supported
Overdrive Control Available Via OSD Setting	Response Time OD
Overdrive OSD Settings	Standard, Advanced, Ultra Fast
Maximum Refresh Rate	144Hz DisplayPort native 165Hz DisplayPort with Overclock
Variable Refresh Rate technology		Native NVIDIA G-sync with hardware module
		AMD FreeSync support via DisplayPort adaptive-sync
		HDMI-VRR for consoles
Variable Refresh Rate Range	30 - 165Hz (DisplayPort)
Motion Blur Reduction Backlight		Available - ULMB Mode
		Blur reduction available also when using G-sync/FreeSync VRR

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 an LG.Display LM270WQA Nano IPS 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.
 

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 G-sync screens (with hardware module) or whether it's an adaptive-sync screen as well, 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:

1. 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.
    

2. 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.
    

3. 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.
    

4. 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.
    

We carried out some initial response time measurements and visual tests in each of the overdrive settings, and at a range of refresh rates. The overdrive control is available in the OSD menu via the 'Response Time OD' option. There are 3 levels available - Standard, Advanced and Ultra fast.

Key Quick Information Box VRR works from both NVIDIA and AMD graphics cards over DisplayPort. Standard response time delivers optimal performance across the refresh rate range Variable overdrive thanks to G-sync module 165Hz overclocked mode works well with fast response times Very good motion clarity ULMB blur reduction mode available and works reasonably well, with some issues with red colours and overshoot artefacts Very low lag thanks to G-sync module

60Hz Refresh Rate

 

We are going to start with 60Hz and work our way up in this section. The lowest 'standard' setting is slightly slower than the 'advanced' setting, with an improvement in overall response times of about 0.5ms as you increase the setting. There is a bit of overshoot that starts to creep in to the measurements in the Advanced mode but in practice they are very hard to see, and overall there's not much visual difference between the two modes. If you push the setting up to the maximum 'ultra fast' mode then the overshoot does become more noticeable with pale halos visible, particularly on lighter backgrounds. For a fixed 60Hz input like a games console or external device the 'advanced' mode is useable but probably doesn't offer much improvement over the 'standard' mode. So it might be simpler to just stick with 'standard' as that's the better option when using G-sync and as we increase the refresh rate...

Increasing Refresh Rate

We increased the refresh rate to 100Hz and re-tested these two modes. The response times have been improved a little now thanks to the variable overdrive feature that is offered from the hardware G-sync module. In standard mode this is fine, but in advanced mode it is a bit too aggressive and it leads to an increase in the overshoot levels as well. There are some pale halos now on lighter content in the advanced mode, so we would recommend sticking to the standard mode here.

It's the same story as the refresh rate is increased higher to 144Hz. Both modes offer a small improvement in response time as the overdrive impulse is being applied more aggressively again. In standard mode it is fine and doesn't lead to any real overshoot. In the advanced mode it is a bit too aggressive and so there's some moderate overshoot measured. In practice to be honest you don't see anything major from the overshoot, but the standard mode is still perfectly fast enough, and avoids any possible overshoot problems anyway. Note that at the maximum native 144Hz refresh rate the response times are very low even in the standard mode, and fast enough to keep up with the frame rate demands (i.e. consistently < 6.94ms G2G).

For reference here are the measurements in the 'ultra fast' mode as well, where the response times are improved slightly further, but at the expense of a bit more overshoot. Again not particularly major in practice, but not worth having to worry about when the standard mode is perfectly fast enough.

 

Overclocking and Variable Refresh Rates (VRR)

Maximum Refresh Rate	144Hz DisplayPort native 165Hz DisplayPort with Overclock
Variable Refresh Rate technology		Native NVIDIA G-sync with hardware module
		AMD FreeSync support via DisplayPort adaptive-sync
		HDMI-VRR for consoles
Variable Refresh Rate Range	30 - 165Hz (DisplayPort)

The native refresh rate of the XG270QG is 144Hz but ViewSonic also offer an overclocking option from within the OSD menu. This can boost the refresh rate up to a maximum 165Hz, although it is not guaranteed and may vary from one sample to another, or depending on your system. If you experience any issues with flickering or artefacts at the overclocked 165Hz mode then you can drop back to the native 144Hz and disable the overclocked feature in the OSD. This overclocking is assisted by the use of the Native G-sync module and is an additional benefit of this model compared with others that use the same panel, like the popular LG 27GL850 (144Hz max).

We enabled the overclocking feature within the OSD menu and tested the response times at 165Hz. Thanks to the variable overdrive feature, the response times are improved a little further as the refresh rate is increased. This is achieved in the standard mode without any noticeable overshoot which is great news. There are some improvements in response times with the overclocked refresh rate, as well as some additional motion clarity and frame rate benefits from running 165Hz as opposed to 144Hz which is good news.
 

Achieving 1ms G2G Response Time?
 

How is the 1ms G2G response time figure achieved then on this screen? We pushed the screen up to the maximum refresh rate and overdrive setting which is usually how these figures are achieved. On other 1ms IPS screens we've tested the figure is often possible, but only at the expense of crazy high levels of overshoot which makes it impractical and unusable in practice. On the XG270QG even the maximum 'ultra fast' mode didn't seem to push response times low enough to reach the 1ms figure. We measured a minimum of around 2.7ms in practice which is still very good, and this was at the expense of moderate levels of overshoot. The overshoot is still too high we felt in this mode, and certainly gets worse and more noticeable in situations where the refresh rate lowers during VRR/G-sync. As expected, the 1ms G2G figure is just marketing here, like it is on other 1ms rated IPS screens.
 

Native G-sync Support and FreeSync

  

The screen has a Native G-sync hardware module (v1) in it and can support variable refresh rates between 30 and 165Hz (with the overclock activated). This offers VRR support for NVIDIA graphics cards of course. We were also pleasantly surprised to see that adaptive-sync works over DisplayPort as well for AMD FreeSync systems. This is one of the screens that features the new G-sync module firmware allowing VRR from non-NVIDIA systems which is great news. Note that HDMI-VRR is not supported though on this screen.

Above: AMD graphics control panel showing support for FreeSync over DisplayPort

While normal (and cheaper) adaptive-sync screens can support both FreeSync and G-sync nowadays, and some even carry a 'G-sync Compatible' certification from NVIDIA for verified levels of performance, a Native G-sync hardware screen remains popular with many gamers. Those with NVIDIA based systems often prefer a Native G-sync screen still given they often have better levels of VRR performance and over a wider refresh rate range. Each Native G-sync screen is thoroughly tested and certified by NVIDIA as well and so the VRR performance can often be superior.

There are other additional benefits of the Native G-sync module including guaranteed low input lag and variable overdrive (as demonstrated in our measurements above). Native G-sync screens are more expensive though, and are more limited in some features like connection options and OSD features so it's often hard to justify the additional cost compared to a decent adaptive-sync display.

The support for G-sync and FreeSync will be very useful given the significant system demands of running a screen at 2560 x 1440 resolution and up to 165Hz refresh rate. It was of course very good to see it included here. You might also want to read our newly updated article about Variable Refresh Rates here for more information.

 

Detailed Response Times

To achieve the optimal performance from the XG270QG we would recommend sticking with the 'standard' response time setting. This works well across all refresh rates including 60Hz inputs and up to the maximum 165Hz overclocked refresh rate. The screen does support variable overdrive which helps control the response times and overshoot across the refresh rate range, making it easy to stick with the 'standard' mode for everything.

The higher refresh rates supported by the screen really do help improve motion clarity and reduce perceived  blur, making the screen far better for gaming than 60Hz-only models. There is only a minor improvement in motion clarity from the increased 144Hz > 165Hz support, but the response times do improve a little as well, and the additional frame rate room will be useful to some. It's not a major change like when going from 60Hz - 144Hz, but every little helps right?

Recommended Settings

     Detailed Measurements at 165Hz, Response Time = Standard

We carried out some further response time measurements at 165Hz which is the maximum refresh rate of the screen. We measured an average 4.3ms G2G response time in this mode which was very good for an IPS panel, and for those keep tabs this is slightly faster than the LG 27GL850 (4.8ms G2G) which is based on the same panel, and has a 144Hz max refresh rate. 100% of the pixel transitions were within the refresh rate window (i.e. consistently less than 6.06ms at 165Hz) which was great news, and meant there was no additional smearing added because of response times that couldn't keep up with the frame rate demands. There was some low levels of overshoot measured, but only on a couple of transitions and we would still rate the overall overshoot level as good. An excellent performance when it comes to response times from an IPS panel again here.

    

Motion Blur Reduction (ULMB mode)

The strobing blur reduction backlight option is available via the 'ULMB' (Ultra Low Motion Blur) setting which is available in some of the preset modes. Only the standard, custom 1 and custom 2 modes. This is only available on the XG270QG at 85, 100 and 120Hz fixed refresh rates, and is not available unfortunately (and oddly) at either the maximum native 144Hz or the overclocked 165Hz modes. Like nearly all other blur reduction modes except a few Asus 'ELMB-sync' models such as the Asus TUF Gaming VG279QM tested recently, this feature cannot be used at the same time as NVIDIA G-sync variable refresh rates.

Example strobing at 120Hz, horizontal scale = 5ms (pulse width = 100)

We measured the on/off strobing using our oscilloscope and confirmed that the strobing is in sync with the refresh rate. So at 120Hz for instance (shown above) the backlight is turned off/on every 8.33ms (120 times per second). As you reduce the refresh rate the strobing remains in sync with it well as you would hope. When you first enable the ULMB mode the screens brightness setting changes up to the maximum 100 setting. You can lower this if you want, but it may be preferable to instead reduce your brightness by controlling the ULMB pulse width as discussed below, as that can also help improve motion clarity as well as reduce the brightness of the display. It should be noted that the response time setting is unavailable when ULMB is enabled.

One annoying thing was that by enabling ULMB the brightness jumps up to the max 100, but when you disable ULMB it doesn't remember where you were before you turned it on, it remembers whatever you set it to when using that mode. So you have to manually set the brightness again to whatever you had it on before ULMB was activated.

There is a setting to control the 'pulse width' of the ULMB mode, which allows you to control the "on" period of the strobing if you want. If you lower the pulse width from the default 100 setting it reduces the on period. This does reduce the brightness output of the screen, but can help reduce the perceived blurring and improve motion clarity even further. We measured the on/off period of the strobe as you reduce this pulse width setting below:

Strobing On/Off period

Pulse width Setting (120Hz)	On period	Off period
100	1.875	6.458
75	1.375	6.658
50	0.875	7.458
25	0.375	7.958
0	0.265	8.068

Brightness Range

We also measured the maximum brightness of the screen (with the brightness control set at 100%) as the pulse width setting was lowered. Note that if you leave pulse width at 100 and instead reduce the backlight brightness control, the luminance is very similar to each of these settings.

Pulse width Setting	Luminance
100	203
75	153
50	103
25	52
0	21

Maximum Blur Reduction Brightness - Display Comparison

For ease of reference we have also provided a comparison table below of all the blur reduction enabled displays we've tested, showing their maximum luminance before blur reduction is turned on (normal mode) and their maximum luminance with the feature enabled. This will give you an idea of the maximum brightness you can expect from each model when using their blur reduction feature, if that is important to you. A lot of people want a brighter display for gaming and sometimes the relatively low maximum luminance from blur reduction modes is a limitation.

These comparisons are with the refresh rate as high as is available for the blur reduction feature to function. For most this is at 100 - 144Hz. You can often achieve a slightly brighter display if you use the feature at compatible lower refresh rates since the strobes are less frequent, but it's not a significant amount. That can also introduce more visible flicker in some situations.

Model	Refresh Rate	Max Normal Luminance Blur Reduction Off (cd/m2)	Max Luminance Blur Reduction On (cd/m2)
Acer Nitro XF252Q	240Hz	413	226
Acer Nitro XV273K	144Hz	503	195
Acer Nitro XV273 X	240Hz	462	210
Acer Predator XB270HU*	100Hz*	327	111
Acer Predator Z35	120Hz	359	111
Asus ROG Strix XG35VQ	100Hz	376	164
Asus ROG Swift PG258Q	144Hz	488	275
Asus ROG Swift PG278Q	120Hz	385	123
Asus ROG Swift PG279Q	120Hz	331	101
Asus TUF Gaming VG279QM	280Hz	378	184
Asus TUF Gaming VG27AQ	165Hz	318	199
BenQ XL2720Z	144Hz	282	119
BenQ XL2730Z	120Hz	309	191
Dell S2716DG	120Hz	328	118
Eizo FG2421	120Hz	386	257
Eizo FS2735	144Hz	331	180
Gigabyte Aorus AD27QD	144Hz	471	129
LG 27GK750F	240Hz	452	199
LG 34GK950F	144Hz	390	235
LG 34UC79G	144Hz	267	141
LG 38UC99	75Hz	308	213
ViewSonic Elite XG270QG	120Hz	434	203

Note: Pulse Width setting at max where applicable.
*Note 2: The Acer XB270HU was later updated to include a 120Hz mode, which will produce a slightly darker maximum luminance
 

Blur Reduction Tests

Of course the main thing we want to test is what improvements the Blur Reduction mode offers when it comes to motion clarity and gaming. The following pursuit camera photos give you an indication of observed motion clarity as the human eye would see it at the top, middle and bottom areas of the screen. These were captured at the maximum supported refresh rate.

Pursuit camera photos capturing perceived motion clarity
Left with ULMB turned off and at 165Hz max refresh rate
Right with ULMB turned on at 120Hz max supported refresh rate (PW = 100), top/middle/bottom areas of the screen

As with most strobing blur reduction backlights it did help improve eye tracking of moving objects across the screen, making them sharper and easier to follow. That's one of the key benefits of this kind of technology. There was noticeable trail images though causes by strobe cross-talk and some other artefacts visible on moving content. At the top of the screen there was a bit of strobe cross talk in front of the moving object, but the middle region seemed to be a bit clearer. At the bottom area of the screen the trailing image was more noticeable still.

There was some noticeable overshoot present as well, a symptom of the response time setting being locked and unavailable - and looks like it has been locked at the 'Advanced' level, or perhaps the 'Ultra Fast' mode given the noticeable dark and pale trails. This was quite noticeable in practice. We also experienced some unusual reddish fringing and colour "flashing" in some moving content situations which isn't commonly seen from these kind of blur reduction modes. It's not really that visible in the above photos, but on some content it appears to produce more of a red trail image in practice. These overshoot, strobe cross talk and unusual red fringing issues meant that the ULMB mode wasn't ideal sadly. It does still help reduce perceived motion blur, and depending on your content you may still find it useful. It just isn't optimal on this model. The PW setting in the OSD is quite handy at helping to reduce a bit of the blur even further, so that was nice to see included. It was odd not to see this mode available at 144Hz and 165Hz refresh rates though.
 

Red Fringing in ULMB Mode

So what causes some of this fringing effect when the ULMB mode is enabled on the XG270QG? This is because of the wide gamut KSF Phosphor backlight used with this Nano IPS panel to enhance the colour gamut and offer the 98% DCI-P3 colour gamut. It should be noted that this has no affect during non-ULMB normal usage, it only causes an issue when ULMB is enabled. It is caused by the abnormal decay behaviour of the red channel phosphor on this backlight.

Above: strobing behaviour of green and blue channels

Measuring the green colour channel with ULMB turned on shows a typical square wave behaviour as the backlight is turned rapidly off and on. This is the same behaviour for the blue channel also.

Above: strobing behaviour of red channel

But when you measure the red channel you see a distorted square wave, with the main problem being the tapered decay as the backlight turns off. Basically the backlight is being turned off rapidly, but the red channel is not keeping up and it takes a bit longer for the red colour on the screen to disappear, relative to the green and blue channels. This results in some red fringing in practice on moving content.

There is an article over at Blurbusters.com which talks about this in a bit more detail, with some further tests included. This looks to be a "feature" of the wide gamut backlight used here, and may be why there was no strobing blur reduction mode provided on LG's Nano IPS models like the 27GL850 or 38GL950G which both feature wide gamut Nano IPS panels (not confirmed).

 

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 now split by panel technology to make life a bit easier and for quicker comparison.

The XG270QG was one of the fastest IPS panels we have tested to date, and the fastest 1440p resolution IPS model in fact. With a 4.3ms G2G average it out-performed in response times the equivalent LG 27GL850 ever so slightly (4.8ms G2G). The ViewSonic does also offer a slightly higher refresh rate up to 165Hz which may bring about some further small improvements in motion clarity and frame rate support. This was achieved with low levels of overshoot too which was excellent news. Another strong performance from the response times of LG.Display's Nano IPS panel technology here.

Additional Gaming Features

• Aspect Ratio Control - the screen has three settings for hardware level aspect ratio control. These are full screen, fix aspect ratio and 1:1 pixel mapping. This should be perfectly adequate to accommodate any non-native aspect ratio inputs.

• Preset Modes - There are quite a few gamer-oriented modes available in the 'Game mode' preset mode menu including FPS, Battle Royale, MOBA and Console. There are also 2x custom modes for you to set up as you like.
   

• Additional features - there are a couple of added features in the OSD which are a 'Dark Boost' feature for bringing out details in darker content through gamma tweaks, and also a cross-hair graphic. ViewSonic also provide a detachable shading hood with the screen which is designed to protect your field of view during gaming.

 

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.

The total lag measured was a very impressive 2.80 ms total. The pixel response times should account for pretty much all of that display lag at around 2.15ms, and so we can say that there appears to be almost no added signal processing lag on this screen at around 0.65ms. This is expected given the use of a hardware G-sync module which pretty much guarantees no lag. An impressive result from this display and making it suitable for fast and competitive gaming.

Movies and Video

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

Category	Display Specs / Measurements	Comments
Size	27" widescreen	Fairly typical for a desktop monitor nowadays and smaller than TV's by a lot
Aspect Ratio	16:9	Well suited to most common 16:9 aspect content and input devices
Resolution	2560 x 1440	Can support native 1080p content only, but not Ultra HD natively
HDCP	Yes	Suitable for encrypted content
Connectivity	1x DisplayPort 1.2 and 1x HDMI 1.4	Useful additional HDMI input for external Blu-ray players or games consoles although only the older v1.4 generation
Cables	DisplayPort only	Only DisplayPort cable provided in the box, no HDMI
Ergonomics	Tilt, height. swivel and rotate	Good range of adjustments suitable to positioning the screen in a variety of angles for different viewing positions. All pretty easy to move around.
Coating	Light Anti-glare	Provides clear, non-grainy image and avoids unwanted reflections of full glossy solutions
Brightness range	87 - 434 cd/m2	Good adjustment range offered including a fairly high peak brightness. Flicker free backlight operation with no PWM
Contrast	811:1 after calibration	Only moderate IPS contrast ratio which should still be ok for most content. Buying an alternative VA technology panel would provide you a higher contrast ratio if you watch a lot of dark content and miss some shadow detail
Preset modes	Movie mode	There is a specific movie which can be customised to your liking, or you can also save one of the 2 user-configurable modes too.
Response times	4.3ms G2G, low overshoot at 144Hz 6.0ms G2G at 60Hz with low overshoot	Response times are excellent overall with no noticeable overshoot when using the optimal response time settings. Stick to the 'standard' response time setting for all refresh rates. Even at 60Hz the response times are decent.
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	Some bleed	Some bleed on our sample from the left hand side corners, but will vary from sample to sample
Audio	Headphone output and 2x 2W speakers	Basic integrated speakers on this model which might be ok for the occasional YouTube clip or mp3 but not much more. A headphone jack is also provided
Aspect Ratio Controls	Full , aspect, 1:1	Decent options to account for non-16:9 format inputs, although the native aspect of the screen is likely to be suitable for a lot of content
PiP / PbP	Neither supported	n/a
HDR support	Nothing meaningful	It can accept an HDR input source, but is only 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 some improvements on the colour side of things for HDR content with the wide colour gamut (98% DCI-P3) and 10-bit colour depth support.

 

Conclusion

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As a gaming screen the XG270QG performed very well overall. It had the fastest response times we have seen to date from any 1440p resolution IPS panel, including low levels of overshoot and the ability to keep up with all refresh rates offered. The 165Hz overclock feature worked well and offered a further boost in response times and a small improvement in motion clarity and frame rate support relative to 144Hz mode. Since the screen features a Native G-sync module it meant that there was reliable and consistent VRR performance across the range, as well as additional benefits like very low lag and variable overdrive which was great. It's primarily aimed at NVIDIA users who want the optimal VRR experience for their system, although we were very pleasantly surprised to see support for adaptive-sync/FreeSync over DisplayPort as well for AMD graphics cards.. There was also an added ULMB blur reduction mode which may be useful to some people, but was not optimal given some of the issues with strobe cross-talk, overshoot artefacts and the red fringing caused by the wide gamut backlight type.

Being a Native G-sync screen has a few disadvantages though. There was no sRGB emulation mode offered and so while the wide DCI-P3 gamut is great for games and multimedia, it might not be as suited to colour critical work if you need to work in the more common sRGB colour space. There was also limited connectivity options available with only 1x DisplayPort and 1x HDMI. Having said that, the XG270QG does pack in a decent range of extras including an often-popular RGB lighting system, various gaming modes and settings, a fully adjustable stand and things like the provided shading hood and headphone holder clip. The IPS panel offered great all round performance with good image quality, wide viewing angles and impressive colours. The contrast ratio was unfortunately mediocre as we've seen from the other Nano IPS panels tested so far.

The XG270QG is a bit more expensive than the popular LG 27GL850. In the US the LG retails for around $100 less, although is not available in some places. In the UK the price difference is a little higher, with the LG available for around �180 less. If you want a bit of a boost when it comes to gaming performance thanks to the G-sync module, overclocked refresh rate and ULMB mode then it's definitely worth considering. The screen is available from most regions via Amazon (affiliate link) where you can check latest pricing and availability.

 

Pros	Cons
The fastest 1440p resolution IPS panel we've tested to date	Lacking an sRGB emulation mode for colour critical work
165Hz overclocked refresh rate works well and gives a small boost compared with 144Hz	ULMB mode is not optimal and has some issues with strobe-cross talk, overshoot and red fringing
Support for both G-sync and FreeSync over DisplayPort	Mediocre contrast ratio after calibration as with other Nano IPS panels