AOC AG254FG

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, 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 observed some faint dynamic interlace pattern artifacts in the form of vertical lines when observing movement or at times when scanning our eyes across the screen. These were only really observable below ~200Hz and even at relatively low refresh rates such as ~60Hz, where they were strongest, they were pretty faint. The ‘Overdrive’ setting and whether VRR was active didn’t affect these, though they were more distinct with ULMB active. They’re too faint for most people to notice or find bothersome.

Responsiveness

Input lag

A sensitive camera and a utility called SMTT 2.0 was used to analyse the latency of the AOC AG254FG. Over 30 repeat readings were taken to help maximise accuracy. Using this method, we calculated 2.13ms (under one frame at 360Hz) of input lag. This is influenced by both the element of input lag you ‘see’ (pixel responsiveness) and the main element you ‘feel’ (signal delay). It indicates a very low signal delay which even sensitive users shouldn’t find bothersome. Note that we don’t have the means to accurately measure input lag with VRR technology active in a VRR environment or HDR active in an HDR environment.

Perceived blur (pursuit photography)

Our responsiveness article covers the key factors related to the monitor responsiveness. An important concept explored in the article is ‘perceived blur’, contributed to by both the pixel responses of the monitor and the movement of your eyes as you track motion on the screen. This second factor dominates on modern monitors, though both factors play an important role. A photography technique called ‘pursuit photography’ is also explored, which uses a moving rather than stationary camera to capture motion in a way that reflects both elements of perceived blur, not just the pixel response element.

The images below are pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at its default speed of 960 pixels per second. This is a good practical speed to take such photographs at and highlights both elements of perceived blur well. The UFOs move across the screen from left to right at a frame rate matching the refresh rate of the display. All three rows of the test are analysed to highlight a range of pixel transitions. The monitor was tested at 60Hz (directly below), 144Hz, 240Hz, 300Hz and 360Hz using various ‘Overdrive’ setting; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. The final column shows the Dell Alienware AW2521HF for reference, where possible, with its optimal setup for responsiveness at each individual refresh rate. This is quite a competent IPS performer at up to 240Hz, when set up optimally (as shown). 120Hz was also tested though not documented here – pixel response behaviour was very similar to 144Hz and there was just a touch of extra perceived blur due to eye movement.

At 60Hz, above, the UFO appears soft and unfocused without clear internal detailing. This reflects a moderate amount of perceived blur due to eye movement. With ‘Overdrive = Off’ there’s just a little conventional ‘powdery’ trailing, particularly for the dark background (top row) and a little for the medium background (middle row). The light background (bottom row) shows a ‘clean’ performance with the ‘Off’ setting. The next setting, ‘Weak’ (perhaps a misnomer) provides a good dose of acceleration and removes pretty much all ‘powdery trailing’ in this test. Just a little remains behind the yellow cockpit area with the dark background. Some overshoot (inverse ghosting) is visible for all transitions, particularly the light background where some ‘halo’ trailing that’s brighter than the background is visible. Overshoot is quite similar if a touch lower here compared to the reference screen. This isn’t particularly strong overshoot – it becomes stronger with the ‘Medium’ setting and stronger again with the ‘Strong’ setting. Based on this analysis and broader observations we consider ‘Weak’ optimal. If you’re particularly sensitive to overshoot ‘Off’ may be worth exploring for relatively low refresh rates like this. Below you can see how things with a significant boost in refresh rate to 144Hz.

At 144Hz, above, the UFO appears significantly narrower with clearer internal detail. This reflects a significant decrease in perceived blur due to eye movement. The demands for a strong performance when it comes to pixel responsiveness are raised significantly now. The ‘Off’ setting provides relatively pronounced ‘powdery’ trailing, reasonably bold for the dark background and still a fair bit for the medium background. The ‘Weak’ setting again provides a significant boost in acceleration, cutting out the ‘powdery’ trailing and replacing it with overshoot. This is a bit more noticeable than at 60Hz, which will reflect the stronger level of acceleration required to speed up the pixel responses at this increased refresh rate. It’s similar to the reference screen overall. The ‘Medium’ setting ramps this overshoot up significantly, with an inky look in places and very bright elsewhere. The ‘Strong’ setting strengthens this further. We consider ‘Weak’ the optimal setting here and feel the overshoot is preferable to the significant conventional trailing with the ‘Off’ setting. Below you can see how things appear with another boost in refresh rate, to 240Hz.

At 240Hz, above, the UFO again appears slightly narrower with better internal detailing. In practice the segmentation is more distinct than it appears in the photos. This reflects a further significant reduction in perceived blur due to eye movement. The pixel response demands have increased significantly now. The ‘Off’ setting is again too slow with widespread conventional trailing. The ‘Weak’ setting cuts down on this effectively, though a bit of ‘powdery’ trailing remains for the dark background. For the medium and light background some overshoot is observed. Overall the reference screen leans towards more widespread ‘powdery’ trailing and lower overshoot. The ‘Medium’ setting ramps up the overshoot levels significantly, bringing it up to clearly distracting levels. The ‘Strong’ setting ramps the overshoot up further. We again consider ‘Weak’ the optimal setting here. Below you can see things with a bit of a bump up to 300Hz.

At 300Hz, above, there’s a further narrowing of the UFO and slight improvement to internal detailing. The segmentation is again more distinct than it appears in the photo, but there is still a slight relative improvement compared to 240Hz as well. This reflects a further reduction in perceived blur due to eye movement. Trailing and overshoot behaviour is quite similar here to 240Hz, though some of the weaknesses are a touch more pronounced due to the increased demands of the refresh rate. The ‘Off’ setting is really too slow to keep up here. The ‘Weak’ setting is optimal, with higher settings than that introducing far too much overshoot. Whilst some stubborn conventional trailing remains behind the UFO cockpit for the dark background. The image below shows a further boost to 360Hz.

At 360Hz, above, there’s a very slight narrowing of the UFO. Though there’s certainly a case to be made of diminishing returns when comparing to the earlier boosts in refresh rate we showed. There’s also a very slightly crisper look to the UFO, at least by eye. These internal differences are not readily apparent in photographs, where the brightness of the screen causes some blending and bleaching of internal details. Even at 360Hz the white notches aren’t distinct and can’t be reliably counted, but the segments of the UFO are certainly distinct with more pronounced segmentation than seen in the photos. The trailing and overshoot behaviour is quite comparable to 300Hz – some of the ‘powdery’ trailing is slightly more pronounced due to the increased pixel response requirements. The ‘Weak’ setting is again optimal, with stronger settings ramping up overshoot far too much and ‘Off’ simply being too slow for a solid 360Hz performance. There are still weaknesses using the ‘Weak’ setting and for some transitions we found the overshoot more eye-catching than it might appear in the photos. We explore this subjectively shortly.

The monitor also includes ULMB which can be activated at 144Hz or 240Hz when the monitor is connected to a compatible Nvidia GPU and running under SDR with G-SYNC disabled in the graphics driver. The setting is found in the ‘G-SYNC Processor’ section of the OSD. This is a strobe backlight setting which forces the backlight to flicker in sync with the refresh rate of the monitor. Sensitivity to this flickering of the backlight varies and some will find it bothersome whilst others may notice accelerated eye fatigue, even if the flickering isn’t actively bothersome to them. The pursuit photographs below were taken with the monitor set to 144Hz using ULMB. ’PW’ here refers to ‘Pulse Width’, which is configurable on the monitor and controls the length of time the backlight spends in its ‘on’ phase. A higher setting here equates to a higher brightness at the expense of motion clarity. It can be adjusted in single unit increments from ‘10’ to ‘100’. The ‘Overdrive’ setting can’t be changed when ULMB is active.

Odd colouration in the background for ‘PW = 10’ is slight glare on the screen amplified by the camera – the monitor brightness is exceptionally low using this setting.

With ULMB active at 144Hz, above, the main object is significantly narrower with clearer internal detailing compared to with the setting deactivated – even if you compare to the maximum 360Hz refresh rate of the screen. The white notches are clear and countable, particularly for lower ‘PW’ settings. In practice, the notches and segmentation is slightly more distinct than it appears in the photos at ‘PW = 50’ and ‘PW = 100’ with the camera bleaching things a bit. Though there is still a slight edge in that respect as you lower ‘PW’, which the photos also reflect. There’s a faint repetition of the object for the dark background, which is broadly termed ‘Strobe Crosstalk’. There’s also overshoot due to the strong acceleration used, with multiple fragments due to the strobe nature of the backlight. The strobe crosstalk and overshoot are both significantly fainter than the main object, so doesn’t have a significant impact on perceived blur and doesn’t tend to detract from the excellent motion clarity improvement ULMB can provide. The image below shows ULMB active at 240Hz.

Wavy patterns surrounding some UFOs in the background are slight image retention. This was only observed during this test and is something we’ve seen on various monitors before. It soon disappeared when using monitor normally.

With ULMB active at 240Hz, above, there’s a further improvement to the ‘crispiness’ of the internal details. This can be noticed by eye to an extent and the ‘PW’ setting appears to have even less impact. Again, the actual clarity of the object and distinctness of segments is improved in person compared to the photos. For example, you can even see the aliasing at the edges of the UFO. ‘PW = 100’ was captured particularly well here and gives a good indication of clarity. In practice lower ‘PW’ settings don’t become less distinct as they appear here, though they don’t really become more distinct at this point either. It’s really the brightness change that you’ll notice by eye. The strobe crosstalk is now quite a bit stronger, quite bold for the dark background and overlapping with overshoot for the initial trailing fragment elsewhere. Overshoot is more distinct as well, with the 240Hz refresh rate significantly more demanding than 144Hz and a higher level of acceleration required. What these photos don’t reflect is the improved ‘connected feel’ that 240Hz provides or the reduced flickering, but all in all we actually prefer the ‘cleaner’ experience at 144Hz with ULMB.

It’s important to be aware that strobe crosstalk varies at different areas of the screen. Not all areas refresh simultaneously, so its appearance can differ depending on how high up or low down on the screen movement is being observed. The image below is a pursuit photo with the UFO shown at various positions of the screen, from top to bottom, at a refresh rate of 144Hz and ULMB active. The ‘- Middle -‘ marker denotes the central region of the screen. You can see that the strobe crosstalk becomes a bit stronger lower down the screen, but is always significantly fainter than the object. Overshoot and strobe crosstalk levels are quite tame towards the central rows, where your eyes mainly focus during competitive gameplay. This indicates quite a good and relatively well-optimised strobe backlight performance. Note that the images below do not accurately show the clarity of the object itself, but allows analysis of strobe crosstalk and other imperfections such as overshoot.

The image below shows the results at 240Hz with ULMB active. The strobe crosstalk is more distinct now. It is displaced in front of the UFO further up the screen and melds into the object lower down. It isn’t too strong centrally, but is still stronger than it was at 144Hz. And the overshoot is more distinct and eye-catching. We do notice these differences in practice so will mainly be focusing our subjective thoughts on the 144Hz ULMB experience. Another advantage is that it’s easier to maintain 144fps solidly than 240fps solidly, making the 144Hz mode more accessible when ULMB is used as VRR can’t be used at the same time.

Responsiveness in games and movies

On various Battlefield titles, at a frame rate keeping pace with the 360Hz refresh rate, the monitor provided a fluid experience. Compared to a 60Hz model or indeed this monitor running at 60Hz (or 60fps), six times as much visual information is presented every second. This massively improves the ‘connected feel’, which describes the precision and fluidity as you interact with the game world. The very low signal delay of the monitor also aids this. The high refresh and frame rate combination also greatly decreases perceived blur, which was demonstrated earlier using Test UFO. For competitive play this combination of exceptional ‘connected feel’ and greatly reduced perceived blur can deliver a nice edge. Making it easier to track enemies and line up shots. We’d stress that this is quite subjective, but we find the initial boost from 60Hz to ~144Hz extremely significant and noticeable. The bump up from there to 240Hz is a nice bonus as well and something we can notice quite readily. The boost to 360Hz from there is less significant in our view, but is still something we noticed and sensitive users could find a welcome thing to have.

Pixel responsiveness is also important when it comes to perceived blur. Many transitions were performed very rapidly and made good use of the 360Hz refresh rate. As demonstrated with Test UFO earlier, though, there are some transitions where the monitor is unable to keep up with the rigorous demands of the 360Hz refresh rate – or indeed lower refresh rates in some cases. Particularly where bright (or strongly saturated) shades are presented against a medium to dark background, there is some reasonably distinct ‘powdery’ trailing. Not ‘smeary’ in appearance, but certainly sufficient to add an extra layer of perceived blur. We also observed quite widespread overshoot, typically as moderately bright ‘halo’ trailing where medium-dark shades moved against medium-bright backgrounds. Or vice-versa, which would produce some dark ‘shadowy’ trailing instead. This wasn’t extreme overshoot, but it still caught our eye in places as it was noticeably brighter or darker than the background and sometimes stood out fairly clearly. Sensitive users could potentially find it bothersome. Although this is the only 360Hz model we’ve tested to date, we have analysed data from a range of other displays (including pursuit photos and measurements). Similar and in some cases more distinct weaknesses can be observed on directly competing models.

We’d normally share observations using Shadow of the Tomb Raider at this point. But even looking at very specific ‘undemanding’ scenes on that title, it was very difficult to reach suitably high frame rates to assess 360Hz performance. Analysing this title doesn’t typically introduce additional issues that wouldn’t be seen on Battlefield, but it does feature a lot of high-contrast scenes. And these same scenes can bring out some of the slower pixel responses performed by this monitor much as they did with Battlefield. We also observed video content at a range of refresh rates, including ~24 – 30fps content on platforms such as Netflix and 60fps YouTube content. We observed a touch of overshoot for 60fps content and slight traces in places at 24fps, but we didn’t find any of this as eye-catching as for higher frame rate gaming. For the ~60fps and ~24 – 30fps content the main barrier to fluidity is the content itself and its low frame rate rather than weaknesses from the monitors pixel responses.

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ULMB (Ultra Low Motion Blur)

Earlier in the review we covered ULMB, including its principles of operation and how it performs using specific tests. As with most strobe backlight features, you can’t use this in a VRR environment so can’t activate G-SYNC at the same time. You can’t use HDR at the same time, either. Your frame rate must match the refresh rate precisely, or you’re left with extremely obvious stuttering or juddering. This stands out in such a clear way due to there being very little perceived blur due to eye movement to mask it. For simplicity we’ll focus on our use of this feature on various Battlefield titles at 144Hz and a solid 144fps. As explored, we found the ‘cleaner’ performance here preferable to using the setting at 240Hz where strobe crosstalk and overshoot was both a fair bit more noticeable. Its also easier to maintain a solid 144fps than 240fps. On the flip-side, 240Hz at matching frame rate improves ‘connected feel’ and flickering is reduced.

The monitor delivered a good low level of perceived blur, with a significant decrease in perceived blur due to eye movement much as explored earlier. Even when turning rapidly or zipping around in an agile vehicle or aircraft, details in the environment maintained good clarity. This included any enemies you might be keeping tabs on. Whilst there was some overshoot and a touch of strobe crosstalk in places, it remained significantly fainter than the main objects which are moving around (or you’re moving your character relative to). So it didn’t significantly impact perceived blur and isn’t something most should find distracting. Because KSF phosphors aren’t used for the backlight, you don’t get clear colourful fringes or flashes with strobe backlight settings like this active. There are other limitations to be aware such as more limited brightness (<200 cd/m² and appearing slightly dimmer due to the nature of strobe backlights). And flickering of the backlight at a frequency matching the refresh rate of the display, which can accelerate visual fatigue even if you’re not consciously aware of it. Overall most will prefer the flexible and flicker-free experience that the ‘normal’ operation of the monitor provides, with G-SYNC available as an option during fluctuations and the ability to use the 360Hz refresh rate. But for those who like strobe backlight settings, at 144Hz at least, this is one of the better ones we’ve come across.

VRR (Variable Refresh Rate) technology

G-SYNC – the technology and activating it

Nvidia G-SYNC is a variable refresh rate technology that can be activated when a compatible Nvidia GPU is connected to a compatible monitor (such as the AOC AG254FG). Our article on the technology explores the principles behind the technology and its benefits, so we won’t be repeating too much of that. Essentially the technology allows the monitor to dynamically adjust its refresh rate to match, where possible, the frame rate outputted by the GPU. When the two are in sync it gets rid of the tearing (VSync off) and stuttering (VSync on) that occurs when the two are desynchronised. An additional benefit for those who hate tearing and usually like to use VSync is a reduction in latency compared to ‘VSync on’ in the variable frame rate environment. This model is a ‘G-SYNC Esports’ model and supports Nvidia’s Reflex Latency Analyzer which was briefly covered in the OSD video.

This monitor supports G-SYNC via DP and HDMI, when connected to a compatible Nvidia GPU such as the RTX 3090 used in our test system. Note that HDR can be activated at the same time as G-SYNC. Once connected up, G-SYNC should be automatically configured and ready to use. There’s usually even a little notification icon in the system tray telling you that a G-SYNC capable display is detected. To check everything is configured correctly, open Nvidia Control Panel and navigate to ‘Display – Set Up G-SYNC’. Ensure that the checkbox for ‘Enable G-SYNC’ is checked, then select your preferred operating mode. As the image below shows, this technology works in both ‘Full Screen’ and ‘Window’ modes, provided the correct option is selected for this. If the G-SYNC options seem to be missing from Nvidia Control Panel, this may be remedied by reconnecting the GPU or possibly connecting the monitor to a different DP output if there’s one available. If the options are still missing, reinstalling the GPU driver or updating this is recommended.

Enable G-SYNC

The AOC supports a variable refresh rate range of 1 – 360Hz (1-240Hz via HDMI). That means that if the game is running up to 360fps, the monitor will adjust its refresh rate to match. When the frame rate rises above 360fps, the monitor will stay at 360Hz and the GPU will respect your VSync in the graphics driver. With ‘VSync on’ the frame rate will not be allowed to rise above 360fps, 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 >360fps). Technically it appeared that the monitor stuck to a multiple of the frame rate with its refresh rate if frame rate dipped below 15fps. But this did the trick to remove tearing and stuttering and was essentially seamlessly integrated – we wouldn’t have known it was doing this if not indicated by the ‘Frame Counter’ feature of the display.

VSync behaviour is configured in the ‘Manage 3D settings’ section of Nvidia Control Panel. It’s labelled ‘Vertical sync’ and can be set to one of the following; ‘On’, ‘Use the 3D application setting’, ‘Off’ or ‘Fast’ (GPU dependent). The ‘Use the 3D application setting’ largely works as you’d expect, but the general recommendation is to set VSync in the graphics driver if you wish to use it as in-game implementations can interfere with the smooth operation of G-SYNC. The ‘Fast’ option enables a technology called ‘Fast Sync’, which only applies above the refresh rate and frame rate ceiling (>360Hz / 360fps). Below this G-SYNC operates as normal, whereas above this a special version of VSync called ‘Fast Sync’ is activated. This is a GPU rather than monitor feature so isn’t something we will explain in detail, but it is designed to reduce tearing at frame rates well above the refresh rate of the monitor. If you’re interested in this technology, which may be the case if you play older or less graphically demanding games at very high frame rates, you should watch this section of a video by Tom Petersen.

Set VSync according to preferences

Some users prefer to leave VSync enabled but use a frame rate limiter set a few frames below the maximum supported (e.g. 357fps) 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’ feature in the ‘Game Setting’ section of the OSD, this will indicate the frame rate of your content if G-SYNC is active. If G-SYNC isn’t active it will simply show the static refresh rate the monitor is running at. The final point to note is that G-SYNC 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.

G-SYNC – the experience

As usual we tested various game titles using G-SYNC and found the experience similar in all cases. Any issues affecting one title but not another suggests a game or GPU driver issue rather than a monitor issue. For simplicity we’ll just focus on our experience across various Battlefield titles in this section. There’s sufficient flexibility there with graphics options and a nice range of scenes available to assess a broad range of refresh rates using our RTX 3090. Where the frame rate dipped at all below 360fps, you’d observe tearing (VSync off) or stuttering (VSync on) without a VRR technology like G-SYNC. With the technology active the refresh rate appropriately synchronised with the frame rate, removing these interruptions. Sensitivity to tearing and stuttering is subjective so not everyone will find the technology as ‘game-changing’ as others. And it’s generally more difficult to notice at high refresh rates and frame rates. It’s still something sensitive users will notice, making the VRR experience attractive to them.

Regardless of how much the frame rate dipped, the technology worked as intended to remove tearing and stuttering from what would otherwise be frame and refresh rate mismatches. Unlike with your typical Adaptive-Sync monitor, effective and tightly-tuned variable overdrive is employed. This loosens off the grey to grey acceleration as refresh rate dips, avoiding overshoot becoming stronger. There was still fairly widespread overshoot, but this is observed even at a solid 360Hz using our preferred ‘Weak’ setting and didn’t become significantly stronger as refresh rate dipped. In fact it appeared slightly reduced at relatively low refresh rates, likely due to the pixel overdrive being slackened off. Another advantage compared to Adaptive-Sync is that the operation is seamless throughout the entire refresh rate range. There isn’t a defined LFC (Low Framerate Compensation) boundary, which is typically 48Hz (48fps), where slight stuttering is introduced as it’s passed in either direction. Although it’s difficult to quantify and isolate, we’ve also experienced a reduction in issues such as micro stuttering if a G-SYNC module is used. And we’ve had others share similar experiences with us.

FreeSync

In addition to supporting G-SYNC on compatible Nvidia GPUs, AMD FreeSync can be used. The monitor includes Adaptive-Sync support via DP, which allows compatible GPUs and systems to use FreeSync. To enable FreeSync as a PC user open ‘AMD Software’. Then click ‘Settings’ (cog icon towards top right) and click on ‘Display’. You should then ensure that the first slider is set to ‘Enabled’. The setting is referred to as ‘Adaptive Sync Compatible’ here, although the exact wording may depend on the driver version you’re using. With our Radeon RX 580, we were able to activate the technology via DP (first image) but not HDMI (second image).

The experience was very much the same as it was with G-SYNC. The key features of the G-SYNC module are accessible, with Adaptive-Sync simply being an alternative way to access the module for compatible AMD hardware. This included variable overdrive and seamless operation throughout the very generous VRR range. Our suggestions regarding use of VSync also apply, but you’re using AMD Software rather than Nvidia Control Panel to control this. Open up AMD Software and click ‘Settings’ (cog icon towards top right), then ‘Graphics’. The setting is listed as ‘Wait for Vertical Refresh’. This configures it globally, but if you wish to configure it for individual games click ‘Game Graphics’ towards the top right. Above this dropdown list there’s a toggle for ‘Radeon Enhanced Sync’ which is AMD’s version of Nvidia’s ‘Fast Sync’.



The ‘Frame Counter’ feature in the ‘Game Setting’ section of the OSD doesn’t work with Adaptive-Sync and will simply show the static refresh rate selected instead. HDR can be used at the same time as Adaptive-Sync, too.

HDR (High Dynamic Range)

On an ideal monitor, HDR (High Dynamic Range) includes very deep dark shades and stunningly bright shades being displayed simultaneously. With the ability to display a broad gamut of shades between these extremes, including more muted pastel shades alongside eye-catching and strongly saturated shades. Ideally, per-pixel illumination would be offered (e.g. self-emissive displays such as OLED), or for LCDs a very large number of precisely controlled dimming zones provided. A solution such as FALD (Full Array Local Dimming) with a generous number of dimming zones, for example. Such solutions allow some areas of the screen to remain very dim whilst others are very bright. Colour reproduction is also an important aspect, with the ultimate goal being support for a huge colour gamut, Rec. 2020. A more achievable near-term goal is support for at least 90% DCI-P3 (Digital Cinema Initiatives standard colour space) coverage. Finally, HDR makes use of at least 10-bit precision per colour channel, so its desirable that the monitor supports at least 10-bits per subpixel. HDR10 is the most widely supported standard used in HDR games and movies and what is supported here.

For games and other full screen applications that support HDR, the AOC AG254FG automatically switches to its HDR operating mode if an HDR signal is provided. Some game titles will activate HDR correctly when the appropriate in-game setting is selected. Others that support HDR will only run in HDR if ‘Use HDR’ is turned on in Windows, too. Related Windows HDR settings are found in the ‘Windows HD Color settings’ (Windows 10) or ‘HDR’ (Windows 11) section of ‘Display settings’ (right click the desktop). If you want to view HDR movie content, ensure ‘Stream HDR Video’ (Windows 10) or ‘Play streaming HDR video’ (Windows 11) is active. Also note that there’s an ‘HDR/SDR brightness balance’ (Windows 10) or ‘SDR content brightness’ (Windows 11) slider that allows you to adjust the overall balance of SDR content if HDR is active in Windows. This is really just a digital brightness slider that only makes changes for SDR content, and you lose contrast by adjusting it. The settings in the OSD are greatly restricted under HDR, even though the image balance is better than some models when viewing SDR content under HDR. We’d recommend only activating HDR in Windows if you’re about to use an HDR application that specifically requires it.

For simplicity we’ll just focus on Shadow of the Tomb Raider for this section. This is a title we’ve tested extensively on a wide range of monitors under HDR and we know it offers a good HDR implementation which highlights strengths and weaknesses well. Weaknesses highlighted here will apply to other HDR content, too. Although our testing focuses on HDR PC gaming using DisplayPort on an RTX 3090, similar observations were made when viewing HDR video content on the Netflix app. There are some additional points to bear in mind if you wish to view such content. We also made similar observations using HDMI, which would be used when viewing HDR content on an HDR compatible games console for example. Testing on both our Nvidia and AMD GPUs showed that the HDR implementation was similar in both cases, too. We were unable to use HDR above 300Hz on our Radeon RX 580, but this could be a limitation with that GPU and its older DP controller hardware.

As is often the case under HDR, you can’t access all of the settings that are available to you under SDR. Settings such as ‘Gamma’ and brightness can’t be adjusted. The brightness setting is referred to as “Peak white (nits)” under HDR but is greyed out and set to ‘80’ (ignore this). If you make changes to colour channels with either control, under SDR, they carry over to HDR as well. Usually the colour channels are locked off under HDR to maximise contrast and allow the monitor to more accurately follow metadata without ‘unexpected’ changes. If you’re not making extreme adjustments here, it’s unlikely to dramatically change your experience either way. We simply used the factory defaults under HDR to maximise contrast and to keep things in-line with our usual testing procedure.

As covered earlier the monitor includes a Dynamic Contrast setting called ‘Variable Backlight’ – which is not a local dimming setting despite the name being used for local dimming on some other models. Under HDR our preference is to set this to ‘Gaming’. The adjustments made are quite tame with this setting, but on the plus side they shouldn’t prove too distracting as it might be if the backlight is constantly adjusting by significant amounts. The ‘Hybrid’ setting seemed to bounce around very rapidly between different brightness levels even when just moving slightly in a scene with mixed content (some dark areas, some lighter areas) – we found this distracting. In some scenes this can happen with the ‘Gaming’ setting, but the adjustments were gentler and less jarring overall. The ‘Desktop’ setting was really very unreactive and we felt the setting might as well be disabled instead at that point. Without the setting active, the monitor simply keeps the backlight at its maximum level and doesn’t deviate from that even if the scene is dominated by darker shades. This lifts up the black depth and depth of dark shades far more than is necessary, just like if you’re viewing dark content under SDR with brightness set to maximum.

The AOC AG254FG is VESA DisplayHDR 400 certified. This is the lowest level of VESA DisplayHDR certification, so only a basic HDR experience is offered here. For the colour gamut this HDR level isn’t at all strict – in this case we measured 73% DCI-P3, which is far too limited for appropriate HDR colour reproduction. This is shown in the representation below, where the red triangle shows the monitor’s colour gamut, the blue triangle DCI-P3 and green triangle sRGB. With the colour gamut sitting much closer to sRGB than the appropriate wider gamuts (DCI-P3 or ideally Rec. 2020), saturation levels are limited for the more vibrant elements such as fires, painted pottery, colourful flowers and some of Lara Croft’s colourful attire. As under SDR, we wouldn’t describe such elements as ‘washed out’, but certainly much less vivid and eye-catching than they could be. And as with SDR, we didn’t observe any obvious issues with oversaturation for more muted shades such as skin tones, vegetation or earthy browns. In places it seemed a bit of ‘artistic licence’ was used to enhance the saturation of some shades, for example some yellowish greens were perhaps brought out a touch too strongly. But this didn’t give a clearly oversaturated look (nor did it overcome the limitations of the gamut). Greater dimming precision for the backlight would also add extra depth to some of the dark and medium shades which is certainly lacking here overall.

Colour gamut 'Test Settings'

The HDR10 pipeline makes use of 10-bits per colour channel, which the monitor supports with additional dithering applied by the GPU (360Hz) or scaler of the monitor (up to 300Hz). We’ve carefully observed a range of content, including fine gradients, on a broad range of monitors where 10-bit is supported monitor side (usually 8-bit + FRC) and where the GPU handles the dithering under HDR. Including comparisons with a given model where the monitor handles the dithering at some refresh rates and the GPU handles it at others. Regardless of how ’10-bit’ is achieved, the resulting image is essentially identical. The enhanced precision of 10-bit enhances the nuanced shade variety, with subtler variations of shade apparent. You can see this for darker shades, for example, where there’s a natural uplift of detail that looks far more natural (and less ‘blocky-looking’) than what a gamma enhancement would provide under SDR. For brighter shades the enhanced nuanced variety helps provide a smoother look to weather effects, smoke and other fine gradients. Whether observing darker or brighter shades, a high level of luminance precision can really help accentuate things – that certainly isn’t offered in this case. The image below shows one of our favourite scenes from Shadow of the Tomb Raider for HDR. Bear in mind this photo is purely for illustrative purposes and in no way represents how the monitor appeared running HDR in person.

This scene was good at highlighting the advantages of the 10-bit precision, with a good mixture or lighter and darker shades. As noted earlier this monitor doesn’t offer local dimming and just offers a Dynamic Contrast setting (‘Variable Backlight’) which we preferred setting to ‘Gaming’. Even with predominantly dark shades displayed on the screen, the black depth and depth of dark shades is nowhere near as deep as you’d expect for a ‘proper’ HDR performance. It does dim a bit compared to with the setting active so gives a less ‘flooded’ look overall, but it could still be described as ‘flooded’ with plenty of ‘IPS glow’ and a far from deep and atmospheric look.

The peak luminance we recorded (440 cd/m²) was pretty limited as far as HDR goes, so these bright elements we referred to such as the light glint on the water or bright areas of daylight sky didn’t stand out in the way they could. There should really be an array of bright to very bright shades displayed with excellent precision and with very bright peaks – that isn’t offered here. The lack of local dimming for the backlight also meant surrounding dark and even medium shades lacked the depth they should have. Not only does this limit the relative ‘pop’ to bright shades, it also saps appropriate depth and atmosphere from areas where darker shades dominate. And it gives things a generally less well-defined look than you’d ideally get, with shadow details simply appearing less ‘inky’ than they could with much stronger contrast. The section of video review below runs through the HDR experience using various scenes in Shadow of the Tomb Raider.

Video review

The video below shows the monitor in action. The camera, processing done and your own screen all affect the output – so it doesn’t accurately represent what you’d see when viewing the monitor in person. It still provides useful visual demonstrations and explanations which help reinforce some of the key points raised in the written piece.

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

Conclusion

The 24.5” screen size provides a relatively compact way to consume the 1920 x 1080 (Full HD) resolution, keeping to a reasonable but not particularly high pixel density. The resolution is relatively easy to drive at high frame rates which is what this monitor is all about. You certainly don’t get the same ‘desktop real estate’, clarity or detail of various higher resolution offerings. The monitor has quite a ‘gamery’ appearance, with a solid-feeling coated metal stand that stretches out unapologetically across the desk. There are plenty of RGB LEDs to enjoy, though many of these are located at the rear and produce little more than a gentle glow even in a dark room. And a logo projector with this AGON PRO model for a little extra visual flair beneath the monitor. These may be viewed as quite gimmicky features, but we did find the ‘QuickSwitch’ OSD controller to be a nice addition for intuitive navigation through the menu system. The OSD itself had quite a few odd quirks, but also a decent array of features such as gamma settings and a very flexible brightness control with a rough indication of brightness rather than just a percentage.

The IPS-type panel and quite strict sRGB coverage provided a look we’d describe as quite ‘rich and natural’. Faithfully producing content within the sRGB colour space, with just a touch of undercoverage but no real over-extension to speak of. This kept content looking largely as the developers intend rather than providing clear oversaturation. Consistency was strong as well. In terms of contrast the monitor aligned closely with our expectations, a touch above the specified 1000:1 even after a bit of tweaking to colour channels. And a moderate but expected level of ‘IPS glow’. The HDR performance of the monitor was really rather lacklustre, though this was to be expected from the specifications. The colour gamut and peak luminance simply isn’t where it needs to be for HDR. Whilst the ‘Variable Backlight’ setting which offers local dimming on some models simply acts as a (fairly tame) Dynamic Contrast setting in this case.

The main reason to buy this monitor is the 360Hz refresh rate. And it did provide a pretty solid 360Hz experience overall, provided you’re tolerant to fairly widespread (though not extreme) overshoot and a small number of transitions providing reasonably distinct ‘powdery’ trailing. Input lag was very low and G-SYNC did its thing with the module (accessible via Adaptive-Sync as well) providing variable overdrive and a seamless experience throughout the very generous range of operation. ULMB provided a pretty good strobe backlight experience in this case as well, particularly at 144Hz where it performed relatively ‘cleanly’ with low strobe crosstalk and overshoot kept in check. This is the only 360Hz model we’ve reviewed to date so we won’t be drawing any detailed technical comparisons here. But we find it tough to outright recommend this or indeed any Full HD monitor at such a high asking price. If you like the sound of this model but just feel it’s too expensive you could also consider the Dell Alienware AW2521H. It lacks the Reflex Latency Analyzer feature, ‘QuickSwitch’ remote and anti-glare hood. But it’s priced significantly lower in some regions, particularly US (~$400 USD vs. ~$750 USD) and still offers a 360Hz experience with G-SYNC module.

Positives	Negatives
Strong colour consistency and close sRGB tracking providing a fairly rich and natural look to things	No support for wide gamuts and slight sRGB undercoverage limit its vibrancy, HDR performance and flexibility
Decent static contrast and basic HDR to provide a different look to things – for a bit of variety	Moderate ‘IPS glow’, screen surface a bit grainy and not particularly ‘light’, unconvincing HDR
Very low input lag, fast pixel responses overall to support the 360Hz refresh rate and solid VRR provided via G-SYNC module	Widespread and in places fairly eye-catching overshoot plus some ‘powdery’ trailing
Excellent ergonomics with a solid feel to the stand, convenient OSD control via ‘QuickSwitch’ remote	Very expensive for a Full HD monitor, quirky OSD, Reflex Latency Analyzer and some of the lighting features could be considered ‘gimmicky’

The bottom line; a well-rounded performance and good price for a large high refresh rate ‘4K’ UHD experience.PC Monitors

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