Introduction

AOC continue to develop their popular AGON series gaming displays, offering some interesting options for consumers at somewhat lower costs than some of the other popular brands like Acer and Asus. Their new AG322QC4 is a 31.5" sized display with a curved format, designed to offer an immersive gaming experience. It features a 2560 x 1440 resolution VA panel with a high 144Hz refresh rate and support for AMD FreeSync 2. A range of extra gaming features are included to enhance the experience as well.

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Specifications and Features

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

The AG322QC4 offers a very good range of connectivity with 2x DisplayPort 1.2, 1 x HDMI 2.0, 1x HDMI 1.4 and even 1x D-sub VGA offered for video connections. There is an additional 2 port USB 3.0 hub, with the ports located on the back of the screen. The screen has an external power supply and comes packaged with the power cable and brick you need. A headphone output connection is provided as well for audio pass-through and the screen includes integrated 2x 5W stereo speakers.

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

Power Consumption

In terms of power consumption the manufacturer lists a typical usage of 75W and <0.5W in standby. We carried out our normal tests to establish its power consumption ourselves.

Out of the box the screen used 46.4W at the default 90% brightness setting. Once calibrated the screen reached 22.8W 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 comparable to the smaller 27 - 31.5" sized screens here, being a little less than the larger ultrawide 34 - 35" models.

Panel and Backlighting

Panel Part and Colour Depth

The AOC AGON AG322QC4 features a Samsung LSM315DP01 SVA (VA-type) technology panel. It is a cell only module without it's own backlight, which is added here by TP Vision. The panel offers an 8-bit colour depth, producing 16.7 million colours.

Screen Coating

The screen coating is a light anti-glare (AG) offering. It isn't a semi-glossy coating, but it is light as seen on other modern VA type panels. Thankfully it isn't a heavily grainy coating like some old IPS panels feature and is also lighter than modern TN Film panel coating. It retains its anti-glare properties to avoid too many unwanted reflections of a full glossy coating, but does not produce too grainy or dirty an image that some thicker AG coatings can.

Backlight Type and Colour Gamut

The screen uses an LED backlight unit which is standard in today's market. This has been added by TPV to the Samsung cell panel being used. There has been some enhancement to the backlight to produce a wider colour space, beyond the typical sRGB gamut. We are checking with AOC how this was achieved, as it is not talked about in the product spec, but expect some enhancement to the backlight itself or perhaps even the use of an enhancement film layer. We will update this review when we have confirmation. Regardless of how it might be achieved, the screen can offer a colour space around 122% sRGB according to some of the regional AOC spec pages, equating to around 90% of the DCI-P3 reference. Oddly this is not really promoted on some of the other AOC spec pages, but confirmed through our measurements. 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

 

Brightness and Contrast

At the full brightness setting in the OSD the maximum luminance reached a very high 363 cd/m² which was a little lower than the specified maximum brightness of 400 cd/m² from the manufacturer. There was a good 320 cd/m² adjustment range in total, so at the minimum setting you could reach down to a low luminance of 43 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 25 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. There is a steeper adjustment between 100 and 90% settings, but a linear relationship from 90 down to 0.

The average contrast ratio of the screen was measured at 2570:1 which was very good thanks to the VA panel, although a little less than the specified 3000:1 from the manufacturer.

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 - 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

• 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 - 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:

There is no sRGB emulation mode offered on this model though so you cannot move to a standard, smaller gamut if you wanted to. You will always have that larger colour space. For a lot of people they will prefer that more colourful and vivid appearance for the intended gaming and multimedia uses.

Default gamma was recorded at 2.2 average with a small 1% overall deviance from the target which was not too bad as an average. The gamma was most off in the lighter tones where it dropped down to 1.92. White point was measured at a too cool 7021k, being 8% out from our target despite the screen being set in the "warm" colour temp mode. We observed that the colour temperature changed and got a little warmer as you lowered the brightness setting on this model. It was measured at 6868k by the time we had simply adjusted the brightness to a more comfortable 25% setting.

Luminance at the default 90% brightness level was recorded at a very bright 312 cd/m² which is too high for prolonged general use, you will need to turn that down. The black depth was 0.12 cd/m² at this default brightness setting, giving us a strong static contrast ratio of 2531:1 thanks to the VA panel. Colour accuracy measurements here should be ignored as they are comparing the screens wider gamut output with an sRGB reference so will be skewed as a result.  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.

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 stuck with the standard ECO mode which allows you to manually select the brightness level, but changed to the 'user' colour temp setting which would allow us to change the RGB channels during the calibration. Gamma had been fairly reliable out of the box in the default mode 1 setting, so we left that as it was. 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.

Average gamma was measured at 2.2 average (leaving a 0% deviance) and sorting out some of the differences across lighter grey shade gamma that we'd seen out of the box. The white point had now been corrected to 6502k which had fixed the too cool 8% deviance we'd seen before. Luminance had been improved thanks to the adjustment to the brightness control and was now being measured at a far more comfortable 121 cd/m². This left us a black depth of 0.05 cd/m² and maintained a strong static contrast ratio of 2275:1. This had dipped a bit because of the RGB adjustments and gamma curve correction but still surpassed any IPS or TN Film technology screens. Colour accuracy of the resulting profile was excellent, with dE average of 0.5 and maximum of 1.5. LaCie would consider colour fidelity to be excellent. Testing the screen with various colour gradients showed smooth transitions with some minor gradation in darker tones and some slight banding introduced through the correction of the gamma curve. 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 pretty good. There was a reliable gamma curve with only a small 1% deviance from our 2.2 average target. White point was a little too cool at 7021k (8% deviance) but thankfully pretty easy to correct through some simple OSD adjustments to the RGB controls. The colour space provided an extended coverage offering ~120% sRGB / 90% DCI-P3 although sadly there was no sRGB emulation mode offered on this model.

When it comes to black depth and contrast ratio the screen performed very well thanks to the VA panel. The calibrated figure of 2275:1 was a little lower than the default out of the box figure (2570:1 average) because of the OSD and graphics card corrections. It was still higher than several other VA panels we've tested which reach around 1800 - 2000:1 typically. It was also a lot higher of course than any IPS or TN Film panel could offer, and a clear strength of this type of panel.

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 some 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 the same as the Samsung C32HG70 unsurprisingly as both are based on the same Samsung SVA panel. 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) in the ultrawide market. 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 sides. Click for larger versions

We captured a photo of an all-black image as viewed from a side angle as shown above. This can help exhibit any glow you might see on different panel technologies. Here we saw some pale glow in places along the top and bottom but this was more related to uniformity issues that we will look at it a moment. There was a slight pale and purple glow but it was also much less than the obvious white glow you get from many IPS panels.

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 good overall on this sample with 88% of the screen within a 10% variance from the centrally calibrated point. The lower left area was a little brighter, ranging up to 129 cd/m² maximum, whereas the upper two corners dropped a little bit down to 101 cd/m² in the most extreme case (upper left).

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 fairly noticeable clouding and blotching of the backlight along the top and bottom edge. It might be quite hard to pick out from the above photo given the strong black depth of the VA panel but it was visible in these tests with the naked eye. You wouldn't notice this in normal day to day use from a head on viewing position, but you could see these lighter clouded areas on dark content and from an angle.

Above: accentuated by a slow shutter speed to demonstrate areas of backlight clouding. Click for larger version

We have also captured the same photo but at a slower shutter speed to try and make this clearer in the photo. This is an exaggeration of what it really looks like to the naked eye, but will highlight the areas of concern on our sample a bit better than the initial photo.

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 AG322QC4 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 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 curved screen format was comfortable and we preferred it for these kind of uses day to day on a large screen like this. That's all down to user-preference of course and there are other flat options out there too in this size.

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 pretty wide viewing angles provided helps minimize on-screen colour shift when viewed from different angles, with no major glow on dark content like you will see from most IPS panels. There was the normal VA off-centre contrast shift which might mean that viewing dark content or doing colour critical work is a little more tricky than on an IPS display. The default setup of the screen offered a decent enough performance with reliable gamma and strong contrast ratio. You might need to tweak the RGB settings to correct the too cool colour temperature. The screen has a wider colour space than normal sRGB screens, offering about 120% sRGB coverage / 90% DCI-P3. This is good if you want to work with wider gamut content or for the intended gaming and HDR uses, but if you were wanting to specifically work with sRGB standard gamut content then that might be a problem. There is no sRGB emulation mode offered by the screen so you might come up against problems working directly with the smaller sRGB colour space.

The brightness range of the screen was very good, with the ability to offer a luminance between 363 and 43 cd/m². This should mean the screen is perfectly useable in a wide variety of ambient light conditions, including darkened rooms. A setting of ~25 in the OSD brightness control should return you a luminance close to 120 cd/m² out of the box. On another positive note, the brightness regulation is controlled without the need for Pulse Width Modulation (PWM), and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry.

There was no audible noise from the screen, even when conducting specific tests which can sometimes cause issues. There is a a range of 'ECO' modes available in the menu but all these really seem to do is cap the brightness setting at different levels, and not impact the rest of the setup. There's no specific reading or text preset mode on the screen as such, so you will need to set up one of the 'Game modes' for every day use. There are however four different low blue light settings which will help reduce the blue spectral output of the backlight and might be useful for reading and office work, making the image a little warmer as a result but being kinder to the eyes.

The screen offers 2x USB 3.0 ports which can be useful. Both are located on the back of the screen so they aren't super-easy to access. Might have been nice to have a couple more, and maybe also offer fast charging support like a lot of other modern screens. There are 2x 5W integrated speakers and a headphone output if you want. There are no further extras like ambient light sensors or card readers which can be useful in office environments. Remember, this is aimed at gamers really. There was a good range of ergonomic adjustments available from the stand allowing you to obtain a comfortable position for a wide variety of angles. The VESA mounting support may also be useful to some people as well for more flexibility.

 
Responsiveness and Gaming

The AG322QC4 is rated by AOC as having a 4ms G2G typical 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 'Overdrive' setting with 4 options available as listed above. The part being used is a Samsung L315DP01 VA 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.
 

Overdrive Setting

 

Refresh Rate

The comparisons in the 'Overdrive' section were done at the maximum 144Hz refresh. Like many high refresh rate screens, especially those with AMD FreeSync, the response time behaviour is dynamically controlled depending on the active refresh rate. We completed the same measurements again while using the 'strong' overdrive setting, but at a range of refresh rates from 144, 120, 100 and all the way down to 60Hz.

We probably need to ignore the 0 > 50 transition here for a moment to draw some comparisons. The overall average response times remained fairly consistent in this 'strong' setting across the refresh rate range, typically around 6.7 - 7.4ms G2G average which was good. The main difference though was the level of overshoot introduced. The amount of overshoot increased quite noticeably as the refresh rate was lowered. At the maximum 144Hz there was no real overshoot detected. At 120Hz (only a small drop in refresh rate) it was starting to reach moderate/high levels, and by the time you reached 100Hz it was significant and pretty obvious in practice. At the lowest 60Hz refresh rate the overshoot was massive (up to 84% in some cases) and very noticeable in moving content with pale halos behind moving objects. Thankfully this overshoot was removed at the higher refresh rates, but you are going to need to make a decision about the refresh rate you can achieve when deciding which 'overdrive' setting to use. If you can consistently manage 120 - 144Hz then the 'strong' mode definitely delivers the best performance, but if they are going to drop below that the overshoot does start to become an issue. We will measure the 'medium' mode as well in a moment at the lower refresh rates.

One other comment was that for some reason the troublesome 0 > 50 black to dark grey transition got slower as you increased the refresh rate. At 60Hz it was fast at 7.8ms but did have some crazy levels of overshoot. At 100Hz the response time was slower at 12.3ms but had no overshoot any more. For some reason this then got slower still as you increased refresh rate and created more noticeable black smearing on some black / dark grey moving content. As we said earlier, thankfully the black > lighter grey transitions were fast in this 'strong' overdrive mode so the black smearing was minimal.

We also took some measurements at 60Hz but in the 'medium' overdrive mode. The 'strong' mode had some very high levels of overshoot and created a lot of pale halos and artefacts in moving content. Thankfully the 'medium' setting toned this down a lot. Sure, the response times were now a fair bit slower at 11.2ms G2G  average (ignoring the slow 0> 50 transition) but the overshoot was pretty much eliminated.

The crux of this is that if you are running the screen at 60Hz including for external inputs, games consoles etc then stick with the 'medium' overdrive setting to avoid the high levels of overshoot. We would also recommend using this mode for refresh rates between 60 - 100Hz, maybe as high up as 120Hz. That will help to avoid the overshoot issues, although response times are a little slower. This does mean that there is more noticeable motion blur unfortunately, and it seems that the AG322QC4 is really optimal if you can reach in to the upper refresh rate range. If you are pushing higher refresh rates above 100Hz, or certainly above 120Hz then we would recommend the 'strong' setting.

Refresh Rate Impact on Motion Clarity and AMD FreeSync

As you increase the refresh rate of the screen there is an additional benefit related to motion clarity due to the way the human eye perceives blur from LCD displays. With the overdrive set to 'strong', the response times remain fairly consistent but the overshoot decreases as the refresh rate increases, and there is also a direct relationship between refresh rate and perceived motion blur levels. There is certainly a lot less blurring at the higher refresh rates, and it is easier to track moving objects across the screen. We would recommend running the screen at the maximum refresh rate if you are able to push the screen to these levels from your graphics card and system. That might vary by game, and over time it will become easier to run 2560 x 1440 @ 144Hz as graphics cards improve too.

One important feature of this screen is the support for AMD FreeSync 2 which offers support for variable refresh rates, helping to avoid tearing and stuttering in games without introducing the lag associated with older Vsync options. It's a very useful technology for when your frame rates fluctuate, especially considering it will take a powerful system to run the screen at its native 2560 x 1440 resolution @ 144Hz. This is only supported from compatible AMD graphics cards, with NVIDIA users not being able to make use of the variable refresh rate sadly.

There is no added blur reduction backlight on this model. We have written a detailed article about such blur reduction backlights so we would encourage you to read that if you are unfamiliar with how these operate and the benefits they can produce on other displays. Some people aren't bothered by these strobed backlights and would rather game with FreeSync and a flicker free experience anyway, so for some people it won't be missed. Others like to use them and may be a bit disappointed that it has been left off here.

 

Detailed Response Time Measurements
Overdrive mode = Strong
Refresh Rate = 144Hz

 

Having determined that the screen performed the best at its maximum 144Hz refresh rate and with the overdrive set to 'Strong', we carried out some further tests over a wider range of pixel transitions. The average G2G response time was now measured at 8.2ms average, although if we ignore the couple of very slow transitions marked in red, the average was actually 7.0ms G2G. This is just about fast enough to keep up with the high 144Hz refresh rate, and we didn't see any real issues with smearing or blurring on moving content in visual tests. There were a couple of pixel transitions from black > dark grey which were a lot slower, which is a fairly typical behaviour for a VA panel. This only impacted the changed between black and dark grey shades, and so the black smearing was not overly obvious. It was less than we'd seen on some other VA panels where the slow transitions also affect changes from black to lighter grey shades, and becomes more problematic.

At this maximum refresh rate and 'Strong' overdrive setting there was basically no overshoot evident, and only a couple of transitions showing anything at all. We know from our earlier tests though that if you lower that refresh rate, or it dips lower when using FreeSync, the overshoot starts to increase quite considerably and becomes a problem at this overdrive setting below around 120Hz. If you can reach the upper refresh rate of this screen then for a VA panel it performs very well really, but the increase in overshoot makes it a little tricky if your refresh rate is going to vary or lower. Dropping down to the 'medium' overdrive setting helps reduce that overshoot at the lower refresh rates, but the response times are quite a bit slower so you get more blurring on moving content in practice.

 

Gaming Comparisons

We have provided a comparison of the AG322QC4 against many other screens we have reviewed. At the optimal settings (144Hz, overdrive set to 'strong') the performance was very good for a VA panel, with an average 8.2ms G2G measured here and fairly low levels of black smearing for a VA panel. It also had low levels of overshoot at these settings which was great news. It put it at a similar level of responsiveness to models like the LG 32GK850G which is a popular VA gaming option in this size.

The trouble with the AG322QC4 is that the response time behaviour is not consistent across different refresh rates sadly. On the LG 32GK850G the measured response times had remained consistent from 60 - 165Hz. However, here on the AOC you had a high level of overshoot introduced as soon as the refresh rate dropped below about 120Hz. If you lowered the overdrive setting to account for this, and reduce the overshoot artefacts, the response times were not as fast.

Additional Gaming Features

• Aspect Ratio Control - the screen has a wide range of settings for hardware level aspect ratio control. This includes options for 'wide', 4:3 aspect and 1:1 pixel mapping. There are also a range of different screen sizes and aspect ratios to choose from like 17" (4:3) or 27" (16:9) for instance.

• Preset Modes - There are quite a lot of preset modes available in the 'Game Mode' menu. This includes presets for FPS, RTS and Racing games, as well as two customisable 'Gamer 1' and 'Gamer 2' modes. You should be able to set up different modes for different gaming uses.

• Shadow control - there is an OSD menu setting which allows you to alter the gamma detail in dark content to make it easier in darker games

• On screen extras - an on-screen crosshair ('dial point' setting) can be enabled via the OSD menu as well which can help accuracy in some games. There is also a frame counter

 

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 6.94ms / 1 frame lag at 144Hz - should be fine for gamers, even at high levels

• Class 2) A lag of 6.94 - 13.88ms / One to two frames at 144Hz - moderate lag but should be fine for many gamers. Caution advised for serious gaming

• Class 3) A lag of more than 13.88ms / more than 2 frames at 144Hz - 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.

There is a setting available in the OSD for "low input lag" as shown above. We tested the lag of the screen with this turned off and on, although to be honest we're not really sure why you'd ever really want to turn it off. With the setting disabled, we measured a total lag of 16.2ms and could estimate a signal processing lag of 12.1ms which was moderately high. Thankfully if you turn low input lag mode on, this is reduced significantly. We now measured 6.40ms of total lag, estimating only 2.30ms of that from a signal processing delay. This was excellent and should make the screen perfectly suitable for fast and high end gaming.

Movies and Video

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

Category	Display Specs / Measurements	Comments
Size	31.5" widescreen	Reasonably large for desktop display
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, but not Ultra HD natively
HDCP	Yes	Suitable for encrypted content
Connectivity	DisplayPort 1.2, HDMI 2.0 and HDMI 1.4	Useful additional HDMI input for external Blu-ray players or games consoles.
Cables	DisplayPort and HDMI	Both provided in the box which is good news
Ergonomics	Tilt, height, swivel	Good full range of adjustments with most being easy to use. Sometimes a bit stiff to operate, but you should be able to position the screen for multiple viewing positions.
Coating	Light Anti-glare	Provides clear, non-grainy image and avoids unwanted reflections of full glossy solutions
Brightness range	43 - 363 cd/m2	Good adjustment range offered. Flicker free backlight operation with no PWM
Contrast	2275:1 after calibration	Very strong contrast ratio thanks to VA panel, helping provide good clarity in shadow detail and darker content. A strength of this technology and easily surpassing other panel technologies.
Preset modes	None	No specific movie preset mode in the menu, but you can set one of the two 'gamer' modes to your liking if you want something different to general or gaming uses
Response times	8.2ms G2G, no overshoot at 144Hz, but 12.1ms at 60Hz	Response time behaviour varies depending on refresh rate. You will need to change to the 'medium' overdrive mode for movies and external devices at 60Hz. Reasonable overall although some dark transitions are still slow due to the VA panel and may result in some black smearing on certain transitions.
Viewing angles	Very good	Not as wide as IPS, but very good for a VA panel and well suited as a technology for movie viewing and darker content. Free from the pale "IPS-glow" on dark content when viewed from an angle that you see on IPS panels.
Backlight bleed	Poor (will vary)	Some fairly noticeable backlight clouding on our sample, pretty apparent in darker room conditions. Will vary from sample to sample.
Audio	2x 5W speakers and headphone out	2x 5W integrated speakers and headphone output provided
Aspect Ratio Controls	Wide, 4:3, 1:1 and a range of sizes/aspects	Good options to account for non-16:9 format inputs if needed although the native aspect of the screen is likely to be suitable for a lot of content
PiP / PbP	Not supported	n/a on this model
HDR support	No real support	Despite the somewhat misleading VESA Display HDR 400 specification, there is no real HDR support from this screen. There is no local dimming to support improvements in the dynamic range. There is also only a small increased peak brightness offered. However, there is a boost in colour space thanks to the 90% DCI-P3 gamut offered at least from the backlight.

Conclusion

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The AGON AG322QC4 is clearly aimed at the gaming market, and focuses on offering a panel with high contrast, high refresh rate and a range of added gaming features to enhance your experience. It was great to see the high refresh rate of 144Hz here for high frame rate demands, smooth gameplay and improved motion clarity. That was paired with a 2560 x 1440 resolution to offer something beyond a lot of 1080p screens, with the VA technology panel bringing some strong all-round performance including the all-important high contrast ratio. We were pleased to see the inclusion of AMD FreeSync for variable refresh rates and to help less powerful systems cope, and the screen had plenty of extra settings and enhancements which you might find useful for gaming. There was also very low input lag and some more vivid, boosted colours thanks to the 90% DCI-P3 gamut backlight.

The response times of the panel were good for a VA panel, and showed pretty low levels of black smearing as well which can often be a problem for this technology. However, we did find that this was only the story if you can run at the optimal settings and 144Hz refresh rate. We did find that if your refresh rate drops lower than about 120Hz you either have to make a sacrifice for slower response times (by changing the overdrive setting), or live with high levels of overshoot which are distracting and problematic in practice. It's most suited as a gaming screen for when you can reliably produce high refresh rates from your system and chosen games we felt.

We've already mentioned the strong VA technology contrast ratio which differentiates this screen and this technology against the wide range of IPS and TN Film models out there. The default setup of the screen was pretty good overall as well, and we welcomed of course the flicker free backlight and range of OSD controls to make adjustments. There is even a (barely advertised) extended colour gamut offering around 120% of the sRGB space, and around 90% DCI-P3. This helps produce more vivid and colourful images for multimedia and gaming which many users will welcome. It did feel very much a gamers screen in design and features and for those who prefer VA panels and the benefits they can offer, it's a good one to consider with a decent size, spec and ultimately price.