AOC AG273QCX

Interlace pattern artifacts

On some monitors, particularly but not exclusively those with high refresh rates, interlace patterns can be seen during certain transitions. We refer to these as ‘interlace pattern artifacts’ but some users refer to them as ‘inversion artifacts’ and others as ‘scan lines’. They may appear as an interference pattern or mesh or interlaced lines which break up a given shade into a darker and lighter version of what is intended. They often catch the eye due to their dynamic nature, on models where they manifest themselves in this way. Alternatively, static interlace patterns may be seen with some shades appearing as faint horizontal or vertical bands of a slightly lighter and slightly darker version of the intended shade.

We did not observe any dynamic ‘interlace pattern artifacts’, although we did observe some static interlace patterns in places. This included but was not limited to certain medium-light greys, various blue shades and dark browns. They broke up into horizontal lines of a slightly lighter and darker variant of the intended shade in places. This static interlacing was reasonably faint and not everybody will notice it or find it bothersome, although sensitive users such as us can find them quite noticeable at times. We don’t find them as eye-catching as ‘dynamic interlace patterns’, which are particularly difficult to ignore if you’re sensitive to them.

Responsiveness

Input lag

We used a small tool called SMTT 2.0 and a sensitive camera to compare the AG273QCX’s latency with a screen of known latency. To help maximise accuracy, over 30 repeat readings were taken. Using this method, we measured 6.15ms (a little under 1 frame @144Hz) of input lag. There was no measurable difference with ‘Low Input Lag’ enabled in the OSD vs. ‘FreeSync’ set to ‘On’ in the OSD. This value is influenced both by the element of input lag you ‘feel’ (signal delay) and the element you ‘see’ (pixel responsiveness). It indicates a fairly low signal delay which shouldn’t bother most users. Unfortunately, we don’t have the means to accurately measure input lag with FreeSync active in a variable refresh rate environment or with HDR active in an HDR environment.

Perceived blur (pursuit photography)

In our article on responsiveness, we explore some of the key concepts related to the topic. One of these very important concepts is known as perceived blur. This is contributed to not only by the pixel responsiveness of the monitor, but also the movement of your eyes as you track movement on this screen. This second factor is actually the key cause of perceived blur on modern monitors, but pixel responses still play an important role. We also introduce a photography technique called ‘pursuit photography’, which uses a moving camera to capture motion on a monitor in a way that reflects both the pixel responsiveness and eye (camera) movement. This contrasts with static photographs or videos which only represent the pixel response element of perceived blur.

The images below are pursuit photographs taken using the UFO Motion Test for ghosting. The test is set to run at its default speed of 960 pixels per second, which is a practical speed for such photographs and sufficient to help highlight key weaknesses. The monitor was tested at 60Hz (directly below), 120Hz and 144Hz with all of the main ‘Overdrive’ settings; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. The ‘Boost’ setting is separate as it is simply a toggle that quickly enables MBR (Motion Blur Reduction) at the maximum level – we explore MBR a little later. Note that you need to have ‘Low Input Lag’ set to ‘On’ in the ‘Game Setting’ section of the OSD or be using FreeSync on an AMD GPU for the ‘Overdrive’ settings to behave properly, as we show below. Otherwise (and this includes using Adaptive-Sync on an Nvidia GPU) it sticks to ‘Off’ regardless of what you select. All rows of the UFO Motion Test were used, to show a range of pixel transitions between various shades. The final columns show two references for comparison, where possible. A Samsung C27HG70 which is a direct competitor to this model and the ViewSonic XG240R which shows how things look where pixel responses aren’t really a limiting factor.

At 60Hz, shown above, the UFO appears soft and unfocused. This reflects a moderate amount of perceived blur due to eye (camera) movement – an element shared with the reference screens. There are also various degrees of trailing behind the object, highlighting some weaknesses with pixel responsiveness. With ‘Overdrive = Off’ there is an extended ‘smeary’ trail for the dark background (top row), some lighter ‘powdery’ trailing for the medium background (middle row) and only a faint hint of trailing for the light background (bottom row). The ‘Weak’ setting cuts back on the trailing for the dark background and medium background, although introduces a little overshoot (inverse ghosting). You can see this as a slight ‘dirty’ (dark) trail behind the UFO cockpit for the medium background and a slight bright (‘halo’) trail behind the UFO for the light background.

The ‘Medium’ setting intensifies this overshoot significantly, making it quite colourful. For the dark background the ‘smeary’ trail persists. The ‘Strong’ setting ramps things up further, strengthening the overshoot. The ‘smeary’ trailing persists for the dark background but appears dirty due to overshoot being mixed in. Note the difference with the C27HG70 reference for this background (bright overshoot, no ‘smeary’ appearance), with the medium and light background appearing similar to the AG273QCX using the ‘Strong’ setting. The XG240R reference is very clean without such distinct weaknesses. We’d consider the ‘Weak’ setting optimal at 60Hz, although individual preferences differ. The following image shows how things look with the refresh rate bumped up to 120Hz.

At 120Hz, shown above, the UFO is significantly narrower with sharper focus. This reflects a significant decrease in perceived blur due to eye movement. There is again varying degrees of trailing behind the object, although the differences between the ‘Overdrive’ settings aren’t as clear. There is a gradual weakening of the trailing, with the ‘Strong’ setting showing the best results. With this setting, there remains some ‘smeary’ trailing for the dark background (but somewhat less than with weaker settings), some ‘powdery’ trailing for the medium background and a little overshoot and some light ‘powdery’ trailing plus a bit of overshoot for the light background. We consider ‘Strong’ to be the optimal setting here. The image below shows what things look like with a slight bump up in refresh rate to 144Hz.

At 144Hz, above, the UFO appears slightly narrower and more sharply focused. Obviously not as significant a difference as comparing 60Hz to 120Hz, but still an improvement. This reflects slightly lower perceived blur due to eye movement. The trailing behind the object is fairly similar to at 120Hz. Because the perceived blur due to eye movement is decreased (object is narrower) and the refresh rate itself has increased, the pixel response requirements for a ‘clean’ performance also increase slightly. The trailing is therefore slightly more extended, although the overall nature of the trailing is quite similar. Most users will appreciate the improved ‘connected feel’ (explored later) and the overall reduction in perceived blur at 144Hz regardless of this. The ‘Strong’ setting is again optimal, without strong overshoot for the transitions shown here and a slight reduction in trailing compared to weaker settings. The C27HG70 reference almost looks like another step up in overdrive over the AG273QCX, with a bit more of a reduction in trailing without any obvious overshoot being introduced for these transitions. The XG240R reference is very clean indeed, the envy of pretty much any other LCD on the market.

Whilst increasing refresh rate clearly reduces perceived blur due to eye movement, for users who want to minimise this as much as possible the monitor has another setting of interest. MBR (Motion Blur Reduction), which is a strobe backlight feature that can be used if ‘FreeSync’ is disabled. This massively reduced eye movement (and hence perceived blur) by causing the backlight to flicker at a frequency matching the refresh rate of the display – either 120Hz or 144Hz. Individual sensitivity to this flickering varies. Some users may notice accelerated eye fatigue when using this setting even if they aren’t actively noticing any flickering. The MBR setting can be adjusted between ‘1’ and ‘20’ in single unit increments – we explore what this means very shortly. The images below show the monitor with MBR set to various settings at 120Hz (directly below) and 144Hz. A range of reference screens are shown with the medium background used, either a Dell S2417DG (120Hz) or AOC AG251FG (144Hz) with their ULMB (‘Ultra Low Motion Blur’) strobe backlight setting active. And an AOC C24G1 with MBR active, set to our preferred settings for that model (‘MBR = 10’ and ‘Overdrive = Strong’).

Before analysing the image above, it’s important to note that the ‘Overdrive’ was set to ‘Strong’ for all pursuit photographs showing the MBR setting in action. Anything lower than this made the trailing too bold and essentially caused some widespread trailing that was appeared as an extension of the object itself rather than a fainter repetition. This duplication of objects with MBR active was quite uncomfortable to look at and made the overall perceived blur reduction less impressive. This image is a pursuit photograph taken at 144Hz with ‘MBR = 15’ and ‘Overdrive = Medium’ so you can see what we’re referring to.

With MBR enabled, at 120Hz (above), you can see that the object itself appears sharper and more detailed than with the technology disabled (regardless of refresh rate). The fine details on the UFO becoming increasingly well-defined as the MBR setting is raised. The MBR values correspond (inversely) to the ‘Pulse Width’. A setting of ‘1’ uses the longest ‘Pulse Width’, meaning that the backlight stays on for a relatively long period during the strobe cycle. This increases brightness at the expense of motion clarity. A setting of ‘20’ indicates the shortest ‘Pulse Width’, decreasing brightness but giving the highest level of motion clarity. We found the setting of ‘MBR = 15’ provided a comfortable balance between clarity and brightness, but the single unit increments allow good flexibility according to individual preferences. You can see a fair amount of trailing behind the UFOs regardless of the setting used, due to slower than optimal pixel responses. The ‘smeary’ trailing observed earlier for the dark background is very much alive here, with a fair degree of trailing for the medium background and relatively trailing for the light background. By comparison, the S2417DG shows no conventional trailing but instead has some overshoot. The C24G1, meanwhile, shows fainter trailing (plus a little overshoot) when compared to the medium background of the AG273. The image below shows how things look at 144Hz.

At 144Hz with MBR (above) things look quite similar overall. There appears to be a slight increase in clarity for the ‘MBR = 15’ setting, although the differences there could be accounted for by how the camera took the images. There are some slight changes to the trailing behind the UFO, but nothing major. What’s more noticeable, really, is the increase in ‘connected feel’ this slight step up provides and some users will appreciate the decreased. The AG251FG reference again shows overshoot rather than conventional trailing, but superb clarity for the object itself. The C24G1 reference shows less bold trailing than the medium background on the AG273.

Another thing you may notice in the above images is that there is sometimes what appears to be trailing in front of the UFO as well, particularly for the dark background. This is ‘Strobe Crosstalk’, which occurs due to the pixel responses not keeping up with the rigorous demands of the refresh cycle. You can see this behind the UFO in places as well, it can be used as a general term to describe trailing observed with a strobe backlight setting active. Because not all parts of the screen refresh simultaneously, the appearance of strobe crosstalk varies at different parts of the screen. This is shown in the below image, which shows pursuit photographs running from the top to bottom of the screen. The monitor was running at 144Hz with ‘MBR = 15’ for this image, as it was our favoured setting overall.

Further up the screen, you can see the strobe crosstalk appearing in front of the object. This explains why the dark background showed this most clearly in the main testing above – it was higher up the screen. Centrally the strobe crosstalk is not visible as things are well optimised here in terms of strobe timing. Further down the screen the strobe crosstalk appears behind the object instead. It is important that the centre of the screen is well optimised, as is the case here, because that is the area of the screen you’ll mainly focus on when gaming. And when focusing on a game you tend to find strobe crosstalk in general less visible. The image below shows the strobe crosstalk at various points of the screen with ‘MBR = 20’.

The strobe crosstalk is visible near the top, in front of the object, but fades away more quickly so that a larger area of the screen is well optimised. Further down the screen the strongest strobe crosstalk behind the object (where it appears duplicated rather than having a fainter trail behind it) starts at a similar point to ‘MBR = 15’. Most users will likely find these differences in strobe crosstalk difficult to notice in practice and should really consider the brightness and overall clarity balance before this.

Responsiveness in games and movies

On Battlefield V the 144Hz refresh rate delivered some clear advantages, where the frame rate kept pace. The ‘connected feel’ was vastly improved compared to running at a significantly lower refresh rate. With the monitor displaying up to 2.4 times as much information every second as a 60Hz monitor (at 60fps), the precision and fluidity as you interact with your character and the game environment is noticeably better. The fairly low input lag also helped in this respect. This combination of high frame rate and refresh rate also significantly decreased overall perceived blur, making it easier to track and engage enemies and giving a competitive advantage on games like this. There were some weaknesses in pixel responsiveness that added to perceived blur, however. When considering most transitions between medium and lighter shades (running around on a bright map, for example, such transitions are common) there was a degree of ‘powdery trailing’ in places. This was generally light and just added a whiff of extra perceived blur, so not hugely detrimental to gameplay. There were some examples of ‘heavy powdery trailing’ as well, which had a more significant impact on perceived and stood out more clearly against amongst faster transitions. There was some overshoot for some transitions as well – partially transparent trails and some ‘shadowy’ trailing that was darker than the object or background colour. But nothing extreme.

The real Achilles heel of VA models like this, though, are the transitions involving darker shades. This includes so-called ‘high contrast transitions’ between bright and significantly darker shades, but also mixtures of very dark and medium-dark shades moving against one another. There were some standout weaknesses on this model where these transitions were concerned, even using our preferred ‘Strong’ setting for ‘Overdrive’. There were instances of significantly slower than optimal pixel transitions, giving a ‘smeary’ trailing in places. This often contained an element of ‘break-up’ trailing whereby some shades would leach out during the transition. The dark military uniform of a solider at night against the sky, for example, might have some of the dark brown or green shades leaching out as ‘break-up’ trailing. The section of the video below gives some examples of this and also looks and some of the faster transitions on this model. As noted, many transitions are enough to avoid these distinct stand-out weaknesses. But some persist and that could annoy some users.

As mentioned in the above section of the video review, we consider the overall pixel on this model to be somewhere in the middle as far as VA models go. Somewhat weaker than what we observed on the Samsung C27HG70 and the AOC C24G1 (even using the ‘Medium’ overdrive setting there). And certainly weaker than on the LG 32GK850G, with appropriate settings. But improved compared to the likes of the AOC Q3279VWF. And quite in-line with the AOC AG322QCX, overall. We also made observations on Shadow of the Tomb Raider. These were largely similar to our observations on BFV and more broadly. This title had a large number of dark shades, with dimly lit interior areas, so ‘smeary’ trailing and ‘break-up’ trailing was quite common. Users probably won’t generally find it distracts too much from the gameplay on titles like this. It’s potentially a lot less bothersome than on titles like BFV, where the added perceived blur and removal of the competitive edge can be more of a nuisance.

Finally, we made some observations on movie content at a variety of frame rates. There were some weaknesses in places, but these were less distinct than the significantly higher frame rate game content. For the ~24 – 30fps content there were no real standout weaknesses. Some traces of ‘break-up’ trailing in places but this didn’t extend far behind the object that’s moving and wasn’t really distracting. The frame rate of the content itself greatly limited fluidity and indeed the pixel response requirements for good performance. The higher frame rate content (50fps) highlighted some slightly more extended ‘break-up’ trailing, some ‘smeary trailing’ and some ‘powdery’ trailing in places. This was less distinct than at significantly higher frame rates and didn’t really mar our enjoyment of these titles.

FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology, an AMD-specific alternative to Nvidia G-SYNC. With this technology, the monitor adjusts its refresh rate dynamically, where possible, to match the frame rate being outputted by the GPU. Both the responsiveness article and the G-SYNC article linked to previously explore the importance of these two elements being synchronised. Essentially, a mismatch between the frame rate and refresh rate can cause stuttering (VSync on) or tearing and juddering (VSync off). An additional benefit of FreeSync is reduced latency compared to running with VSync on, within the variable frame rate environment in which it operates.

FreeSync requires a compatible AMD GPU such as the Radeon RX 580 used in our test system. There is a list of GPUs which support the technology here, with the expectation that future AMD GPUs will also support the feature. The monitor itself must support ‘VESA Adaptive-Sync’ for at least one of its display connectors, as this is the protocol that FreeSync uses. The AG273QCX supports FreeSync via DP and HDMI on compatible GPUs and systems. More specifically, ‘FreeSync 2’ is supported by the monitor, encompassing HDR support (this feature is not AMD-specific) and a relatively generous effective range of operation. HDR can be activated (at the same time as FreeSync) via DP 1.4 or HDMI 2.0. If fully installed, AMD drivers feature Radeon Settings, which makes activation of the technology very simple and something that usually occurs automatically. First make sure that you have ‘FreeSync’ set to ‘On’ in the ‘Game Setting’ section of the OSD. You should then make sure the GPU driver is setup correctly to use FreeSync, so open ‘AMD Radeon Settings’ and click on ‘Display’. You should then ensure that the first slider, ‘AMD FreeSync’, is set to ‘On’. If you hover over this, it will also report the variable refresh rate display supported by the display.



The AOC supports a variable refresh rate range of 48 – 144Hz. That means that if the game is running between 48fps and 144fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 144fps, the monitor will stay at 144Hz and the GPU will respect your selection of ‘VSync on’ or ‘VSync off’ in the graphics driver. With ‘VSync on’ the frame rate will not be allowed to rise above 144fps, at which point VSync activates and imposes the usual associated latency penalty. With ‘VSync off’ the frame rate is free to climb as high as the GPU will output (potentially >144fps). AMD LFC (Low Framerate Compensation) is also supported by this model, which means that the refresh rate will stick to multiples of the frame rate where it falls below the 48Hz (48fps) floor of operation for FreeSync. If a game ran at 35fps, for example, the refresh rate would be 70Hz to help keep tearing and stuttering at bay. This feature is used regardless of VSync setting, so it’s only above the ceiling of operation where the VSync setting makes a difference.

VSync is configured in the ‘Gaming’ section of ‘Radeon Settings’, where it is referred to as ‘Wait for Vertical Refresh’. You can either configure this globally under ‘Global Settings’ or for each game individually. The default is ‘Off, unless application specifies’ which means that VSync will only be active if you enable it within the game itself, if there is such an option. Such an option does usually exist – it may be called ‘sync every frame’ or something along those lines rather than simply ‘VSync’. Most users will probably wish to enable VSync when using FreeSync to ensure that they don’t get any tearing. You’d therefore select either the third or fourth option in the list, shown in the image below. The final option, ‘Enhanced Sync’, is a relatively new addition to the driver. This is an alternative to VSync which allows the frame rate to rise above the refresh rate (no VSync latency penalty) whilst potentially keeping the experience free from tearing or juddering. This requires that the frame rate comfortably exceeds the refresh rate, not just peaks slightly above it. We won’t be going into this in detail as it’s a GPU feature than a monitor feature.



Some users prefer to leave VSync enabled but use a frame rate limiter set a few frames below the maximum supported (e.g. 141fps) instead, avoiding any VSync latency penalty at frame rates near the ceiling of operation or tearing from frame rates rising above the refresh rate. If you activate the ‘Frame Counter’ in the ‘Game Setting’ section of the OSD, this will display the refresh rate of the display and therefore indicate the frame rate if ‘FreeSync’ is active and the frame rate is within the variable refresh rate range of the display. Finally, it’s worth noting that FreeSync only removes stuttering or juddering related to mismatches between frame rate and refresh rate. It can’t compensate for other interruptions to smooth game play, for example network latency or insufficient system memory. Some game engines will also show stuttering (or ‘hitching’) for various other reasons which won’t be eliminated by the technology.

FreeSync – the experience

We tested various game titles with FreeSync active on the monitor and found the experience to be very similar on all of them, at a given refresh rate. Any issues identified on one title but not another would indicate an issue with the game or GPU driver rather than a monitor issue. So instead of focusing on various titles and repeating observations, we’ll simply be focusing on Battlefield V for this section. This title offers appropriate graphical flexibility to allow the full range of refresh rates to be observed with FreeSync active. With our lowly Radeon RX 580, it certainly wasn’t easy to maintain a constant 144fps, even on single player without particularly intense action on screen. Using rather modest graphics settings, we were able to achieve decent triple digit frame rates. Without FreeSync active, there was obvious stuttering (VSync enabled) or tearing (VSync enabled) from frame rate and refresh rate mismatches. Individual sensitivity to this varies, but as we’re sensitive to this it was a massive relief having these nuisances removed. We did prefer the higher frame rates (ideally 144fps or as close as possible) vs. lower frame rates (~100fps) in this observation range. That’s because higher frame rates still lower perceived blur and improve ‘connected feel’, the frame rate itself is still important.

With graphics settings turned up further, we observed further drops in frame rate. As triple digits became a distant memory and the frame rate dropped well below 100fps, the difference in ‘connected feel’ and increase in perceived blur was painfully obvious to us. However; it was still very welcome having the tearing and stuttering from frame and refresh rate mismatches removed. We also noticed an increase in overshoot (inverse ghosting) as the frame rate dipped and therefore the refresh rate also dipped. This is something we commonly observe on FreeSync monitors and it’s something that G-SYNC models generally handle a lot better. Nvidia uses something called ‘variable overdrive’ which slackens off the aggressiveness of the pixel overdrive appropriately as refresh rate reduces. FreeSync monitors tend to be tuned with their highest native refresh rate in mind, in this case 144Hz. The issue is tied to the pixel response behaviour at different refresh rates rather than frame rates, so you don’t observe this increased overshoot with FreeSync disabled and running the monitor at a static 144Hz. Having said that, the overshoot was not extreme and not as widespread or as ‘in your face’ as on some FreeSync models at similar refresh rates. Nor was it as obvious as at a static 60Hz refresh rate. And if you’re particularly sensitive to overshoot and are commonly at these low frame rates, you could slacken off the ‘Overdrive’ to ‘Weak’. This increases conventional trailing, making powdery trailing more widespread, but some users may prefer this to the overshoot.

Where frame rate dipped below the floor of operation (48fps – 48Hz), the monitor employed LFC to keep the refresh rate at a multiple of the refresh rate. This worked very effectively to remove tearing and stuttering from less clean divisions of refresh rate and frame rate. And in some respects, it was nice when LFC kicked in as the overshoot levels reduced (it’s more noticeable at 48fps/48Hz than 49fps/98Hz). These very low frame rates certainly didn’t appeal to us, though, due to the significant increase in perceived blur and complete lack of ‘connected feel’ compared to much higher frame rates. Another perhaps smaller issue is that, when LFC activates or deactivates, there is momentary stuttering. If you’re frequently going above and below the LFC boundary this could become jarring, but it’s not extreme stuttering and doesn’t last long if you’re just passing this point occasionally.

A final but important point is that we observed some flickering at times. This generally occurred where there were significant and sudden fluctuations in frame rate, of perhaps 40fps or more. The screen would flicker for about a second or two before things stabilised. There was also flickering during some very low frame rate content, such as in the menus of some games. Some flickering during significant frame drops and during very low frame rate action (or lack of) is actually quite common on VA models with variable refresh rate technology. They’re quite sensitive to the voltage changes that occur as refresh rate fluctuates. We felt this was somewhat more widespread on this model than usual, though. We also observed some instances of flickering where the frame rate was more stable and also higher. It was difficult to pinpoint exactly what caused this and it wasn’t particularly common or something we found bothersome. The same can’t be said for the flickering we observed with Adaptive-Sync on our Nvidia GPU, which we cover below.

Nvidia Adaptive-Sync (‘G-SYNC Compatible’)

As noted earlier, AMD FreeSync makes use of Adaptive-Sync technology on a compatible monitor. As of driver version 417.71, users with Nvidia GPUs (GTX 10 series and newer) and Windows 10 can also make use of this Variable Refresh Rate (VRR) technology. When a monitor is used in this way, it is something which Nvidia refers to as ‘G-SYNC Compatible’. Some models are specifically validated as G-SYNC compatible, which means they have been specifically tested by Nvidia and pass specific quality checks. With the AG273QCX, you need to connect the monitor up via DisplayPort and enable ‘FreeSync’ in the ‘Game Settings’ section of the OSD. When you open up Nvidia Control Panel, you should then see ‘Set up G-SYNC’ listed in the ‘Display’ section. Ensure the ‘Enable G-SYNC, G-SYNC Compatible’ checkbox and ‘Enable settings for the selected display model’ is checked as shown below. Press OK, then turn the monitor off then on again so that it re-establishes connection – the technology should now be active.



You will also see in the image above that it states: “Selected Display in not validated as G-SYNC Compatible.” This means Nvidia hasn’t specifically tested and validated the display, not that it doesn’t work. And indeed it did. We found the Nvidia Adaptive-Sync (G-SYNC compatible) experience much the same as using AMD FreeSync on this model in terms of the technology removing tearing and stuttering from frame rate and refresh rate mismatches. All of our observations regarding different refresh rate and frame rate ranges, somewhat increased overshoot as this reduces etc. also applies. As with FreeSync, HDR could also be activated at the same time if you like. The technology also worked with an LFC-like technology where the frame rate fell below the refresh rate of the display. The refresh rate stuck to a multiple of the frame rate, keeping tearing and stuttering from uneven divisions of the two at bay. There were notable differences compared to our experience with FreeSync on this model, however.

1) The floor of operation for VRR was 60Hz (60fps) rather than 48Hz (48fps). Or 55Hz (55fps) if you’ve set the monitor to 120Hz. As above, an LFC-like technology was available.

2) The ‘Overdrive’ setting did not function with Adaptive-Sync enabled on our Nvidia GPU. All settings behaved as ‘Off’.

3) There was widespread flickering. As with FreeSync, this occurred during significant drops in frame rate and in some in-game menus. But there were widespread instances of flickering where frame rate was much more stable. And this included high frame rates well into the triple digits and approaching the ceiling of operation (144fps). It was most noticeable at high brightness levels or when viewing in dimmer lighting conditions – having HDR active made it particularly eye-catching. But some users would notice this at much lower brightness settings, too. This section of the video review shows the flickering effect.

Our suggestions regarding use of VSync also apply, but obviously you’re using Nvidia Control Panel rather than Radeon Settings to control this. The setting is found in ‘Manage 3D settings’ under ‘Vertical sync’, where the final option (‘Fast’) is equivalent to AMD’s ‘Enhanced Sync’ setting. You’ll also notice ‘G-SYNC Compatible’ listed under ‘Monitor Technology’ in this section, as shown below. Make sure this is selected (it should be if you’ve set everything up correctly in ‘Set up G-SYNC’).



Finally, note again that you can activate the ‘Frame Counter’ feature in the ‘Game Setting’ section of the OSD to see if the technology is working. This will fluctuate as frame rate fluctuates, whereas if Adaptive-Sync isn’t being used it will stay at the static refresh rate you’ve selected. Given the issues with flickering and the pixel overdrive not functioning, some Nvidia GPU users will want to leave this technology disabled on this model. But sensitivity to flickering and overall motion performance varies so some users may find it beneficial regardless.

MBR (Motion Blur Reduction)

We’ve already introduced the MBR (Motion Blur Reduction) feature, its principles of operation and how it performs using specific tests. We’ve also explained that our preferred settings to use with this feature are a 144Hz refresh rate with ‘Overdrive = Strong’ and ‘MBR = 15’. When using MBR or any strobe backlight feature, it’s very important that your frame rate matches the refresh rate you’re running at. Otherwise you are greeted with extremely obvious stuttering or juddering, which stands out due to there being very little perceived blur to mask it. FreeSync can’t be used with MBR active. With BFV running at a solid 144fps, the setting did justice to its namesake and greatly reduced perceived blur. This gave a very nice competitive edge, as the game environment and friends and foes within it remained more sharply focused even during rapid character movement. Even with the drawbacks of MBR, explored in the two proceeding paragraphs, some users will find this competitive edge a massive plus and very much like using this setting. And it’s generally something that users might use for a few hours at a time during competitive gaming rather than something they use constantly.

There were still some weaknesses which prevented this from being an entirely ‘clean’ experience. As we highlighted earlier, there is some strobe crosstalk on this model. It’s not as noticeable when gaming and focusing on that rather than an artificially constrained environment like the UFO Motion Tests for ghosting. The trailing generally appears a fair bit fainter than the object itself, separated into various increasingly faint fragments due to the strobing nature of the backlight with this setting. Sometimes these fragments contain overshoot, other times they simply replace the instances of ‘powdery’ trailing observed with MBR deactivated. The weakest pixel transitions on this model, which caused the more noticeable ‘smeary’ and ‘break-up’ trailing persisted. The fragmented nature of the trailing weakened the intensity of this in some cases, although there were some instances where it appeared largely as it did without MBR active. Even with this, there was a definite reduction in perceived blur overall with the feature active. And the ‘connected feel’ that the 144Hz at 144fps brought with it was still very much intact.

We also noticed an edge in motion clarity when observing film content with MBR active. This was most noticeable for higher refresh rate content such as 60fps YouTube videos, although even here the difference was more subtle than when observing higher frame rate game content. For this 60fps content it was better to set the refresh rate to 120Hz rather than 144Hz, too, to reduce juddering. Even for lower frame rate film content (~24 – 30fps) there was a reduction in perceived blur with MBR active, although the frame rate itself greatly limited fluidity and the difference was far from dramatic. Sensitivity to flickering varies – but even if a user doesn’t notice a distinct flickering, they may notice accelerated eye fatigue with MBR active. You may also notice distinct flashes of green and magenta at times when observing white or very light greys on the screen. Particularly when scanning your eyes across the screen where thin areas of these very light shades are placed in front of a significantly darker background. This is common on strobe backlight models with a wide colour gamut, such as this, and isn’t bothersome to everyone.

HDR (High Dynamic Range)

HDR (High Dynamic Range) on a monitor describes the ability to distinctly display very deep dark shades and very bright light shades simultaneously. The display of a large range of shades between these, from very muted to highly saturated is also important. Ideally the monitor would be able to control the illumination of each pixel individually, a capability reserved for backlightless technologies such as OLED. For LCDs, it’s desirable for the monitor to use a complex backlight solution with hundreds if not more dimming zones – referred to as FALD (Full Array Local Dimming). By controlling illumination with high precision, the monitor can correctly display intricate mixtures of dark and light content. Some parts of the screen can be illuminated to high brightness levels so that bright shades have good ‘pop’ and stand out nicely, whilst other sections of the screen displaying darker shades would be illuminated to much lower levels. Keeping the black depth nice and low and the deeper shades appearing suitably ‘inky’. But HDR isn’t just about contrast on a monitor, it’s also about being able to display a huge range of colours. The ultimate goal with this in mind is coverage of a massive colour gamut known as Rec. 2020. A more achievable near-term aim is for a monitor to offer 90% DCI-P3 (a Digital Cinema Initiatives standard colour space). Finally, HDR makes use of 10-bit+ precision per channel, so it’s desirable for the monitor to support (at least) 10-bits per subpixel.

It is specifically the HDR10 pipeline which is currently used on monitors and the common standard supported most widely in games and other applications. For most games and other full screen applications that support HDR, the AOC AG273QCX will automatically switch into its HDR operating mode. You’ll know HDR is active on the monitor as you’ll see that many options are greyed out in the menu and the ‘Luminance’ menu will only allow you to select one of a few ‘Eco Mode’ settings which are specific to HDR. These are; ‘HDR’, ‘HDR Picture’, ‘HDR Movie’ and ‘HDR Game’. As of the latest Windows 10 update, relevant HDR settings in Windows are found in ‘Windows HD Color settings’ which can be accessed via ‘Display settings’ (right click the desktop). Most game titles will activate HDR correctly when the appropriate in-game setting is selected. A minority of game titles that support HDR will only run in HDR if the setting is active in Windows as well. Specifically, the toggle which says ‘Play HDR games and apps’. If you want to view HDR movies on a compatible web browser, for example, you’d also need to activate the ‘Stream HDR Video’ setting. These settings are shown below. Also note that there’s a slider that allows you to adjust the overall balance of SDR content if HDR is active in Windows. However; regardless of the settings used here, SDR content never appeared correct if HDR was active in Windows. Users should therefore only activate HDR in Windows if they’re about to specifically use an HDR application that requires it, and have it deactivated when viewing normal SDR content on the monitor.

The AOC AG273QCX is VESA DisplayHDR 400 certified. This is the most basic level of certification that VESA will give to an HDR capable display and it means that only a basic HDR experience is offered, with some but not all desirable HDR boxes ticked. One area where the AOC achieves and indeed exceeds the VESA DisplayHDR 400 requirements is colour gamut, with 90% DCI-P3 specified by the manufacturer. This is technically sufficient for the DisplayHDR 1000 certification level, but only in terms of the colour gamut. Our colorimeter software doesn’t allow direct comparison with DCI-P3, but as explored earlier, the colour gamut is certainly wide on this model with plenty of extension beyond sRGB. The manufacturer’s claim is certainly believable. It’s worth remembering that DCI-P3 is the near-term standard game developers and HDR movie directors have in mind when creating HDR content, so having good coverage of this colour space is important for HDR.

Although our testing is focused on HDR PC gaming, our observations also apply to HDR movie content and running HDR on a compatible games console. The experience is dictated and, in many respects limited, by the capabilities of the screen itself. We also found the experience very similar whether using our AMD or Nvidia GPU. We tested a range of game titles but will simply be focusing on Battlefield V and Shadow of the Tomb Raider. Both titles have good HDR implementations. We’ve seen HDR in action on these titles or those with a very similar HDR implementation (such as BF1) on a wide range of monitors, so we know the experience is very good if the monitor itself offers a good HDR implementation. As noted earlier there are various HDR settings listed as ‘Eco Mode’ settings in the ‘Luminance’ menu. All but the default ‘HDR’ setting provided obvious oversaturation (with a crushing of shade variety) and extreme over-sharpening. Oddly, this excessive sharpness was applied if you switched to another setting then back to the default ‘HDR’ setting. We preferred how things were displayed by default under HDR, which applies a milder sharpness filter, so simply left this setting alone after activating HDR. The monitor made good use of the generous colour gamut, toning saturation down somewhat in places and giving a more natural look to the environments as a result. There was technically a bit of oversaturation in places, but this was toned down significantly and many users will like the balance struck under HDR on the AOC. There was less ‘pop’ to lighter greens, whilst some very lush deep greens were appropriately maintained. A lessening of excessive red hue to some skin tones and rich reddish brown earth etc. Shades which were clearly intended to be vibrant, such as the reds and oranges of fires, brightly coloured flowers and painted objects stood out very nicely still (with saturation clearly beyond the boundaries of sRGB). Just as a reminder, the image below shows the comfortable extension beyond sRGB of the AOC’s native colour gamut.

Colour gamut 'Test Settings'

In addition to putting the colour gamut to good use, the monitor also supports 10-bit colour reproduction (8-bit + dithering, which is quite usual where 10-bit is supported) under HDR. This allows enhanced precision within the HDR pipeline. It appears that this dithering stage is handled by the monitor if set to 120Hz or 60Hz, but offloaded to the GPU if the monitor is set to 144Hz. At least, according to what is reported in Nvidia Control Panel. We made careful observations (including of fine gradients) under HDR and did not notice a different in the resulting static image quality between refresh rates. There was clearly a very different look to the game world on both Battlefield V and Shadow of the Tomb Raider under HDR – and in many respects a more realistic look. The shadow detail and nuanced subtle shade variety was greatly enhanced, with much better distinction between some of the closely matching shades. It helped give better 3D structure to objects and simply gave a more defined look. Fine gradients such as clouds, fog, smoke and rays from the sun also showed smoother and more natural-looking transitions. So as far as VESA DisplayHDR 400 implementations go, AG273QCX provided one of the better experiences we’ve had on a monitor.

One significant drawback of this level of VESA DisplayHDR certification, though, is that it does not mandate any sort of local dimming. This model’s backlight is controlled as one unit, which as noted in the contrast section means there is no contrast advantage to using HDR. You can also see some abrupt fluctuations in brightness at times as the overall balance of light and dark on the scene changes. And occasionally you may observe a flickering effect if the backlight seemingly can’t decide how bright or dim to go and seems to dither between a fairly bright and fairly dim state. Under HDR there is an overall brightness advantage, though, as peak luminance is increased. And indeed HDR did give a very bright look to both of the game titles, particularly in daylight scenes. In fact we found this quite uncomfortable for extended durations even in a reasonably well-lit room. With effective local dimming (or, ideally, per-pixel illumination) you’d get small areas of the screen that are really bright to help bright elements like flames, the sun and lamps stand out against darker surroundings. And there would be well-defined bright shades of varying luminance levels. Whilst the darker surroundings would have good depth to them, again with a good variety of luminance levels. The bright shades really didn’t stand out in the same way as on some HDR models (with effective local dimming and higher peak luminance), so there wasn’t the same ‘wow’ factor. And because there was no local dimming, darker areas had their luminance levels dragged up as well. The depth and atmosphere to darker scenes was severely lacking. It isn’t like these game titles just show black and nothing else – the backlight has to ramp itself up so that brighter elements still look reasonable. The section of the video review below runs through the HDR experience on the monitor and gives some more specific in-game examples of the technology in action.

The 27” 2560 x 1440 curved experience

We’ve tested a broad range of curved monitors, of various curvatures, sizes and panel types. The 27” panel with 1800R curve on the AG273QCX is a moderate curve, which as usual has a far more subtle effect on the image than pictures and videos tend to suggest. It’s easy for users to be put off the curve by looking at pictures where things can appear odd and at times even distorted. And users who require geometric perfection, perhaps designers, may have good reason for wanting to stick with a flat screen. When actually using the monitor, it’s something you quickly adapt to and essentially forget it’s even there. It draws you into the experience just a little more, but feels very natural. Some users might find it enhances viewing comfort by creating a more uniform distance between your eyes and various sections of the screen. This is an aspect manufacturers are often keen to promote. We found the monitor comfortable to use in general, although we don’t generally find flat monitors uncomfortable simply because they are flat. The 2560 x 1440 (WQHD) resolution is another was also one which we found comfortable to use on a screen of this size, something which many users would agree with. It provides a good but not exceptional pixel density and gives a good amount of useful desktop ‘real-estate’ (without scaling, for many users). It also provides a good level of detail for games, suitably high resolution images and other content. The images below show the monitor in action on the desktop. As usual the curve appears exaggerated, they’re just intended to give a rough idea of how things might look.

For gaming the curve provided just a subtle feeling of extra depth, drawing you in just a bit without feeling uncomfortable or unnatural. As we observed on the desktop, the effect was subtle. Steeper curves and wider screens can enhance this effect, but in this case it’s certainly a minor addition to the experience. The images below show a variety of games running on the monitor. Again, they exaggerate the curve and do not accurately reflect how the monitor appears in person (in terms of image quality or the curve). They are purely for illustrative purposes.

Interpolation and upscaling

Some users may wish to use the monitor at a lower resolution than the native 2560 x 1440 (WQHD). Either for performance reasons or because they’re using a device (such as a games console) that doesn’t support the full native resolution. The monitor provides scaling functionality via both DP and HDMI. It can be run at resolutions such as 1920 x 1080 (Full HD) at up to 120Hz and use an interpolation (scaling) process to fill the pixels of the screen up. If you’re connected via HDMI 2.0, the monitor also supports an upscaled 3840 x 2160 (‘4K’ UHD) signal at up to 60Hz. This will be useful if you’re using a games console which supports that resolution but not the native 2560 x 1440. To ensure the monitor rather than GPU is handling the scaling process, as a PC user, you need to ensure the GPU driver is correctly configured so that the GPU doesn’t take over the scaling process. For AMD users that are using this monitor, the driver is set up correctly by default to allow the monitor to interpolate where possible. Nvidia users should open Nvidia Control Panel and navigate to ‘Display – Adjust desktop size and position’. Ensure that ‘No Scaling’ is selected and ‘Perform scaling on:’ is set to ‘Display’ as shown in the following image.

The monitor offers various ‘Image Ratio’ settings in the ‘Extra’ section of the OSD, when you’re running at a non-native resolution at a refresh rate that supports interpolation. There is a ‘1:1’ option which will only use the pixels called for in the source resolution, filling out the rest as black borders but maintaining a crisp and unsoftened output (e.g. of 1920 x 1080 pixels). There are a range of other modes as explored in this video, which accompanies our OSD video. The default, ‘Wide’, uses all of the pixels on the monitor. With the monitor running at 1920 x 1080 (Full HD) using its interpolation process, there was a moderate degree of softening compared to running the Full HD resolution on a screen of similar size. Textures and edges were not as clearly defined, although things did not appear extremely soft either as some interpolation processes cause. Particularly if you’re viewing from a reasonable distance back and using the monitor for console gaming, the Full HD output is certainly of reasonable enough quality to be used. If you’re sitting at a desk as a PC user, you’ll want to consider lowering other graphics options before the resolution. Although this is always the case regardless of how good an interpolation process may or may not be.

As usual, if you’re running the monitor at 2560 x 1440 and viewing 1920 x 1080 content (for example a video over the internet or a Blu-ray, using movie software) then it is the GPU and software that handles the upscaling. That’s got nothing to do with the monitor itself – there is a little bit of softening to the image compared to viewing such content on a native Full HD monitor, but it’s not extreme and shouldn’t bother most users.

Video review

The video below summarises some of the key points raised in this written review and shows the monitor in action. The video review is designed to complement the written piece and is not nearly as comprehensive.

Timestamps:
Features & Aesthetics
Contrast
Colour reproduction
HDR (High Dynamic Range)
Responsiveness

Conclusion

For users after a good all-round gaming experience, 27” 2560 x 1440 models are popular. They come in three main flavours, each with their distinct pros and cons – TN, IPS and VA. The AOC AG273QCX, of the AGON 3 series, takes the VA path. As usual for models with these characteristics, the screen is also curved (to 1800R). The screen size and resolution provided a good pixel density for a multitude of uses, bringing nice detail and clarity to games and high resolution images. And keeping text looking quite crisp but also readable without scaling (mileage may vary). The curve was a less noteworthy addition, which for some users might be a good thing. It didn’t dramatically change the experience, just drawing you in a bit more and giving a slight feeling of extra depth. Once you’re used to it, which shouldn’t take long for most users, you really forget it’s there. The monitor coupled this with full ergonomic flexibility and a very robust stand design. ‘Light FX’ RGB LEDs also feature to illuminate the area behind and beneath the monitor in various customisable ways. We didn’t find these LEDs as bright as we’d like, to use as effective bias lighting, but they at least offered more utility than some solutions. Those which you have to look at directly to see working – which isn’t much use when there’s a wall directly behind your monitor.

The overall contrast performance was strong, in line with panel specifications and exceeding what we measured on the Samsung C27HG70 we tested without its local dimming feature active. This gave dark scenes in games a nice atmosphere, much better than on non-VA LCD panels without any sort of fancy (local dimming) backlighting technology. There were the usual VA caveats in the form of ‘VA glow’ and ‘black crush’, but neither was at an extreme level. Indeed the ‘VA glow’ was somewhat reduced compared to on the aforementioned Samsung, although wasn’t as low as we’ve seen on some flat screen models of this size and panel type. The handling of brighter shades was good, overall, with the screen surface imparting a slight but not ‘heavy’ or ‘smeary’ graininess. Certainly a marked improvement from the AOC AG273QCG (very different G-SYNC cousin of this model), although not the smoothest screen surface particularly amongst VA panels.

The monitor was easy to adjust in the OSD to achieve a vibrant and well-balanced image. The colour gamut offered generous extension beyond sRGB and the panel itself delivered good colour consistency, amongst the best we’ve seen from a VA panel in that respect. Even with the slight saturation losses and ‘dulling’ near the extreme edges and bottom of the screen, the image appeared unmistakably vibrant but varied (in a good way) from a normal viewing position. The saturation and gamma shifts became more pronounced if you’re sitting closer or viewing the screen from an angle. And either way, they’re the key reason we’d recommend an IPS-type panel over any VA for colour-critical work. But for general usage from a normal viewing position, they’re much less of an issue. The monitor also supports HDR, more specifically VESA DisplayHDR 400. Provided you don’t select one of the ‘weird’ alternative HDR modes and just stick with the defaults, the experience was actually one of the better VESA DisplayHDR 400 level experiences we’ve come across. The handing of nuanced shade variety (particularly shadow detailing), overall saturation levels and just the general look it gave to lighter areas of the image was pleasing. But it didn’t offer any local dimming, so dark scene handling was lacklustre. And those ‘wow’ moments that stronger peak luminance could provide weren’t there.

The responsiveness is never the highlight of reviewing a VA model. But some models are still better than others. All things considered, we’d put this one somewhere in the middle. It certainly delivered a nice ‘connected feel’ with fairly low input lag and 144Hz output. And quite a few pixel transitions were fast enough to provide only some ‘powdery’ trailing for suitably high frame rates. But there were also some noteworthy instances of ‘smeary’ trailing and ‘break-up’ trailing, somewhat more eye-catching than we saw on the Samsung C27HG70 for example. Although not as extreme as on some VA models. These sorts of weaknesses could certainly bother some users, but not everyone is so sensitive to them. We would’ve preferred to see more distance between the ‘Overdrive’ settings and a ‘Strong’ setting that actually lived up to its name. Adaptive-Sync also worked on the monitor, as part of ‘FreeSync 2’ or for compatible Nvidia GPUs as part of ‘G-SYNC compatible mode’. The removal of tearing and stuttering from frame rate and refresh rate mismatches worked in both cases, exactly as a VRR (Variable Refresh Rate) technology should achieve. But there were some issues with flickering, particularly with the Nvidia GPU, that may sour the experience for some users. The ineffective pixel overdrive control whilst using Adaptive-Sync on our Nvidia GPU wasn’t ideal, either. The MBR setting was certainly not the ‘cleanest’ we’ve seen due to some of these weaknesses persisting, but it still worked and offered good flexibility as well.

Overall, we feel this monitor provides quite a pleasant all-round gaming performance. If you’re primarily interested in vibrant colour output and strong contrast, with decent responsiveness on the side, then this model is worth considering. If you’re more interested in strong responsiveness and a competitive edge then the Dell S2719DGF is a more suitable solution. Users will no doubt be considering both of these models and cross-comparing, so one important factor will also be price. At time of review the AOC is by far the more expensive option, and many users will consider it a bit overpriced. Whether that premium is worth paying will largely come down to where your own individual preferences lie.

The bottom line; a monitor with vibrant but varied colour output and strong contrast plus a half-decent HDR implementation, but some issues with pixel responsiveness and VRR that may put some users off.

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