AOC AG241QX

Responsiveness

Input lag

A small utility called SMTT 2.0 was used alongside a very sensitive camera to analyse the latency of the AG241QX. To aid accuracy we took over 30 repeat readings. Using this method, we calculated 7.68ms (over 1 frame at 144Hz) of input lag. With ‘Low Input Lag’ set to ‘On’ in the ‘Game Setting’ section of the OSD, this was reduced decreased to 3.60ms (just over ½ a frame at 144Hz). This option is greyed out when connected to a GPU with FreeSync enabled, but our testing suggests that the latency is similar to having ‘Low Input Lag’ set to ‘On’. We don’t have an accurate means to test this in-game, but we were pleased with the felt latency of this monitor when connected to a FreeSync-compatible GPU. Note that these values are influenced both by the element you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). Especially with ‘Low Input Lag’ enabled or when operating in ‘FreeSync’ mode, the signal delay seems to be very low on this model.

Perceived blur (pursuit photography)

In our responsiveness article we look at various factors affecting the responsiveness of a monitor. One of the key concepts explored here is ‘perceived blur’, and the notion that this is contributed to by both the pixel responsiveness of the monitor and the movement of your eyes as you track motion on the screen. This second factor is more significant on a modern LCD such as this. We also introduce ‘pursuit photography’, which is a technique that captures motion on a monitor in a way that more accurately reflects what the eye sees compared to static photography or videos. A moving camera is used to not only capture the pixel responses of the monitor but also reflect movement of the eye (camera) – both key elements of perceived blur.

The following images are pursuit photographs taken using the UFO Motion Test for ghosting, with the test running at 960 pixels per second. This is a practical speed for such photography and highlights both perceived blur factors nicely. The monitor is tested at various refresh rates (60Hz, 100Hz and 144Hz) with various ‘Overdrive’ settings; ‘Off’, ‘Weak’, ‘Medium’ and ‘Strong’. The middle row of the test (medium cyan background) is used here. The final column in the image shows some reference shots. The first of these is a Samsung S27A750D set to 60Hz, full brightness (eliminates PWM) and using its optimal response time setting. The second reference shot is taken from a Dell S2716DG running at 144Hz, using its optimal response time setting. These reference shots show more or less how things should look where pixel responsiveness isn’t a limiting factor (except for a little overshoot on the Dell). Note that any interlacing patterns are moiré from the camera and that the UFO moves from left to right on the screen at a frame rate matching the refresh rate.

At 60Hz there is a significant amount of blur, as the object itself appears quite soft and wide. This indicates a high amount of perceived blur due to eye movement, linked to the 60Hz refresh rate (note the reference screen UFO also appears soft and wide). There is also a significant amount of trailing behind the object, particularly with ‘Overdrive’ set to ‘Off’. This is due to slower than optimal pixel responses. The trailing is weakened using the ‘Weak’ setting and quite similar to the ‘Medium’ setting. A definite improvement over ‘Off’, but not perfect or reflective of the reference screen. The ‘Strong’ setting introduces obvious inverse ghosting (overshoot) with a bright halo trail behind the object.

At 100Hz the UFO becomes narrower and somewhat more detailed, indicative of the sort of reduction in perceived blur you’d expect as refresh rate (and frame rate) is increased. There is also a fair amount of trailing behind the object, again due to slower than optimal pixel response times. This is most pronounced using the ‘Off’ setting, somewhat reduced but still significant using the ‘Weak’ setting and slightly weaker but still visible using the ‘Medium’ setting. The ‘Strong’ setting again introduces obvious overshoot, albeit marginally weaker than for the 60Hz example.

At 144Hz the UFO is more sharply focused and less wide again, with some of the linear details on the UFO body clearer and the entire object (from cockpit to legs) appearing more sharply focused. This is due to perceived blur once again becoming lower as the refresh rate is increased. The pixel responses again contribute to the overall perceived blur, with a noticeable trail behind the object. This is most obvious with the ‘Off’ setting, somewhat reduced using ‘Weak’ and very slightly reduced but still visible using ‘Medium’. The ‘Strong’ setting again introduces some noticeable overshoot, although this is slightly weaker again compared to lower refresh rates for this particular example.

Using the monitor more generally affirms that the ‘Medium’ setting is optimal on this monitor. ‘Strong’ provides obvious overshoot during some transitions which is far more visible than for the transitions shown here. The ‘Weak’ setting improves upon ‘Off’ considerably. Although the ‘Medium’ setting doesn’t provide a huge advantage over ‘Weak’, it does still give a bit of an edge overall without negative consequences.

Responsiveness in games and movies

On Battlefield 1 (BF1), where frame rate kept pace with refresh rate (i.e. 144fps @ 144Hz) the monitor provided an excellent ‘connected feel’ when interacting to the game world. The character or vehicle that the character is driving reacted very quickly to user input and the flow of these interactions was excellent. This is exactly the sort of thing you’d hope for from a high refresh rate monitor with low latency. The perceived blur was also massively cut down compared what you’d see on a 60Hz monitor, or at lower frame rates in general. This largely reflected what was observed on the UFO Motion Test for ghosting earlier. Also reflecting this was the fact that there was a bit of additional trailing in places from slower than optimal pixel responses. So whilst the perceived blur was far reduced compared to lower refresh rates, it was not quite at the level of some of the best 144Hz performers. There was an additional ‘mask’ of blur which reduced texture detail when moving rapidly and introduced a slight trail behind some objects as well. This was particularly noticeable when moving rapidly, for example flying an aircraft, where the difference in perceived blur was fairly pronounced. Not as pronounced as the benefit you get compared to lower refresh rates or frame rates, but certainly still a significant difference between this and something like the Dell S2716DG. A model we happened to be running side-by-side with this one for some of the responsiveness testing. There was no noticeable overshoot on the AG241QX, which is good.

We also observed the monitor on Dirt Rally. Again, the combination of high frame rate and refresh rate provided an excellent ‘connected feel’ between man and machine. Or should that be, man, virtual man and virtual machine? Either way the cars on this game reacted in a very slick fashion to user input, with a certain flow that is lacking on lower refresh rate models regardless of their input lag. The perceived blur was also hugely reduced compared to such models, helping the game environments flow past in quite a smooth fashion and keeping the track and objects (and indeed other cars) somewhat more visible and detailed when racing. There was again a bit of trailing in places beyond what you’d ideally see which contributed to perceived blur. This meant that objects and textures appeared slightly less sharply-focused than they otherwise would, although the difference wasn’t too dramatic. There was again no noticeable overshoot which can be quite eye-catching, so that was pleasing to see.

We also observed the responsiveness of the monitor using our Blu-ray test titles. There were no weaknesses imparted by pixel responses being either too slow (i.e. additional trailing) or too strongly accelerated (i.e. overshoot). The 24fps or so at which these titles ran was the main barrier to fluidity here and the 144Hz refresh rate provided a bit of an advantage over 60fps due to an even division of frames. Because 24 divides evenly into 144 (6 times), there is a reduction in juddering that would be caused on a 60Hz monitor by uneven frame division into the refresh rate.

FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology which provides a ‘red team’ alternative to Nvidia G-SYNC. The monitor dynamically adjusts its refresh rate so that, where possible, it matches the frame rate being outputted by the GPU. Both our responsiveness article and the G-SYNC article linked to explore the importance of this synchronisation. Essentially a mismatch between the refresh and frame rate can cause stuttering (VSync on) or tearing and juddering (VSync off). FreeSync also promises reduced latency compared to running your game with VSync enabled, in the variable frame rate environment in which it operates.

FreeSync requires a compatible AMD GPU such as the Club3D Radeon R9 290 royalAce used on our test system. Alternative GPUs which support this are listed here – future AMD GPUs should support this feature as well. It also requires a monitor that supports ‘VESA Adaptive-Sync’ for one or more of its display connectors, as this is the protocol that FreeSync uses. This system contrast with G-SYNC which requires the use of a proprietary G-SYNC board and hence is a lower cost solution for manufacturers to implement. The AOC AG241QX supports FreeSync via DP 1.2a (or ‘DP 1.2a+’). AMD’s recent drivers include Radeon Software Crimson, which makes activation of the technology very straightforward. It should be enabled automatically, but you can check its status by opening ‘AMD Radeon Settings’ and clicking 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. Note that the image below is for a different monitor and is just used as an example here.



The AOC supports a variable refresh rate range of 30 – 144Hz. Beyond 144Hz the GPU respects 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) and the refresh rate of the monitor will stay at the maximum supported (144Hz). AMD LFC (Low Framerate Compensation) is also supported, which means that the monitors refresh rate will stick to multiples of the frame rate where it falls below the 30Hz (30fps) floor of operation. If the game was running at 20fps, for example, the refresh rate would be 40Hz to keep tearing and stuttering in check. This feature is used regardless of VSync setting.

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 final option in the list, shown in the image below.



There are a few final things to note related to the technology. Firstly, the application must be running in fullscreen mode, not a window (borderless or otherwise). Secondly, this monitor does not provide any obvious ‘at a glance’ indication that FreeSync is active, such as a change of power LED colour. In the ‘Extra’ section of the OSD it will have ‘FreeSync’ listed as the ‘V. Frequency’ if the technology is enabled in the graphics driver, but this does not tell you whether it is currently being used by an application or not. Hopefully the difference that the technology makes in practice will be an obvious enough indication that it is working, however.

FreeSync – the experience

We have shared our experiences with AMD FreeSync on several reviews already, so our regular readers will know that we find it to be a nice addition to monitors like this. We have been enjoying playing BF1, which at time of writing is a new release whilst testing this aspect of the monitor extensively. Fortuitous timing, as the flexibility that this title offers in terms of graphical settings and the relative demands that imposes is perfect for testing FreeSync. Using automatically configured graphics settings, on our Radeon 290 (hardly a powerhouse of a GPU by modern standards) yielded somewhere around 100fps most of the time, sometimes dipping to around 80fps and sometimes climbing a little above to perhaps 110fps. Without FreeSync active and therefore using this monitor as a ‘regular’ 144Hz monitor there was obvious (to our eyes) tearing with VSync disabled. There was also an obvious juddering effect as different sections of the screen displayed different frames – so even if the tear line itself wasn’t visible, there was a certain discontinuity to the action. With VSync enabled there was jarring stuttering, which certainly impeded our enjoyment in this title.

Enabling FreeSync, as you’d hope, gets rid of both elements. The refresh rate of the monitor dynamically adjusts to the frame rate of the game, preventing these visual disruptions. The overall visual fluidity (level of perceived motion blur) and ‘connected feel’ as we interacted with the game world was very good as well. However; things did improve in this respect at even higher frame rates, so if graphical options were reduced so that the frame rate was closer to 144fps. Easily the starker comparison, though, was increasing the graphical settings to reduce frame rate. As things dropped well below 100fps and closer to 60fps, things looked and felt (shock, horror) much like they do on a 60Hz LCD – even with FreeSync. This technology does not change the fact that relatively low frame rates are relatively low frame rates. Although the difference between this sort of frame rate and much higher frame rates was palpable, the lack of tearing and stuttering was still a profound bonus. Indeed, tearing and stuttering both become even more noticeable at reduced frame rates such as this.

Pushing the graphics further and reducing the frame rate well below 60fps (sometimes to around 30fps) made the game look and feel obviously sluggish. Not a pleasant experience at all. Still, there was no tearing or stuttering from frame rate and refresh rate mismatches – a welcome bonus which makes the experience painful rather than very painful. It’s important to remember that sensitivity to tearing and stuttering does vary. For some users, who are rather sensitive to such things, variable refresh rate technologies such as this are real game-changers at any frame rate. A wonderful breath of fresh air. For others, the difference isn’t so obvious – particularly at high frame rates where tearing and stuttering are inherently less obvious. For us, we always prefer a frame rate that’s as high as possible on titles such as Battlefield 1 regardless of the presence of FreeSync or similar technologies. But where the frame rate does drop below the traditional static refresh rate (144Hz, for example) we find such technologies very welcome indeed.

The 2560 x 1440 (WQHD) experience on a 23.8” screen

Most monitors with a 2560 x 1440 (WQHD) resolution are 27”, giving a pixel density of 108.79 PPI (Pixels Per Inch). With a 23.8” screen, the pixel density is increased to 123.41 PPI (13.4% higher than 27” WQHD models) on the AOC AG241QX. We have already compared these two screen sizes and resolutions fairly comprehensively in our review of the Dell P2416D, which also features a 23.8” WQHD screen. Rather than repeating what we’ve already said, we’d advise you to take a look at the relevant section of that review (just after ‘Responsiveness in games and movies’) for a descriptive and graphical comparison. We would simply like to reiterate a few basic points. Firstly, we don’t feel that the pixel density difference is really dramatic enough compared to a 27” WQHD for most users to struggle to read text if they find 27” WQHD comfortable. Text and UI elements are slightly smaller (~13.4%) without scaling, but certainly much more readable than on models with a UHD resolution and screen size of 32” or smaller. The images below will give you an idea of the size of text and UI elements relative to the screen size and also how much real-estate the WQHD resolution provides on the AOC.

Many gamers are quite comfortable with the ~24” screen size from their preferred seating position. It certainly doesn’t feel like a small screen, unless you’re sitting quite far back or are used to much larger screens. Not as engrossing, perhaps, but on the flip-side you can observe more of the action using your central cone of vision rather than peripheral vision, which could be considered a competitive advantage. In terms of detail levels you have a slight edge over 27” WQHD models, but this isn’t really profound enough to change the experience that much. It’s a relatively subtle difference and certainly isn’t as impactful as the change coming from 1920 x 1080 or going up to 3840 x 2160 on a screen of this sort of size. Or in fact a 27” screen. Whilst it doesn’t have the same ‘wow factor’ as the UHD resolution, it is a pleasing pixel density which can make games look attractive. Particularly those with nice graphics in the first place, such as Battlefield 1 (BF1) shown in the images below. These are just for illustrative purposes and in no way represent what the monitor looks like in person.

Interpolation and upscaling

You might be looking to run the monitor at a lower resolution, for example 1920 x 1080 (Full HD), either to make a game much less demanding graphically or because you’re using a device such as games console that does not support the native 2560 x 1440 resolution. When running the monitor at a non-native resolution such as 1920 x 1080 (assuming 1:1 pixel mapping isn’t selected) an interpolation process is used to scale the Full HD image across the 2560 x 1440 pixels of the monitor. For AMD users everything is configured automatically so that the monitor will handle this. Nvidia GPU users need to ensure the monitor rather than GPU is handling the scaling process for optimal results. 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 interpolation process on the AG241QX provides a moderate but not excessive degree of softening compared to a native 1920 x 1080 monitor of similar size. There is a loss of texture detail and definition and things look a bit soft around the edges, but a decent degree of sharpness is still maintained that far surpasses the interpolation process of some monitors and indeed the GPU-handled scaling. The monitor is therefore very much useable for secondary use in 1920 x 1080, for example when connecting to games consoles. As usual, if you keep the monitor at 2560 x 1440 and view 1920 x 1080 (Full HD) content such as a Blu-ray on the PC itself then the GPU or software ‘upscales’. The monitor simply outputs 2560 x 1440 as normal without interpolation – so things look exactly as they do on any other 2560 x 1440 model in terms of the scaling process. This gives a bit of softening compared to native Full HD but nothing dramatic. Some users may actually find running the monitor at 1920 x 1080 and using its own interpolation process to provide slightly better results, but it will be down to individual preferences.

Conclusion

We’re no stranger to monitors with high refresh rates, such as 144Hz. There is an ever-increasing range of these models, with various sizes, resolutions and panel types. The AOC AGON AG241QX makes use of a 2560 x 1440 panel with a screen area measuring 23.8” diagonal. So in terms of pixel density, overall screen ‘real-estate’ and practicality we actually find this to be a good choice. The TN panel technology is also potentially the fastest of the LCD panel types and in many respects makes sense for a gaming monitor – leaving aside the fact that the only 23.8” panels with such a refresh rate are TN anyway. We breathed something of a sigh of relief when we first turned the monitor on, as it displayed decent richness straight from the box. It was obvious it didn’t have a big gamma problem, with a central gamma of 2.0 or even lower being disturbingly common on high refresh rate TN models. The usual viewing angle related weaknesses and perceived gamma and saturation shifts associated with the panel technology were certainly there, as you’d expect, but overall colour representation was decent.

One thing we were quite disappointed by was the use of a medium matte anti-glare screen surface with a fairly grainy surface texture. This disappointment was fuelled somewhat by the relatively recent changes on the Dell S2716DG, whereby the original screen surface (which is similar to that on the AG241QX) was ditched in favour of a lighter matte surface. The difference this made to the overall look of the image, particularly in terms of clarity and overall image smoothness was quite pronounced. Although we have yet to test it ourselves, we’ve been reliably informed by multiple users that this new light matte screen surface is also used on the S2417DG. That being the case, it’s a shame AOC decided to use the AOC M238DTN01.0 rather than M238DTN01.2 – with the thinner bezels and a lighter matte screen surface being key advantages for the latter.

When it came to contrast the AG241QX performed largely as we’d expect from such a monitor and indeed from the specified 1000:1, with a static contrast of over 900:1 following adjustments made to our ‘Test Settings’. We found the ‘Low Blue Light’ settings particularly impressive, owing to the fact static contrast was unaffected despite them clearly having the desired impact on the image and the blue colour channel. The lack of ‘IPS glow’ was certainly nice, although the perceived gamma shifts did affect the representation of dark shades by revealing extra detail further down the screen. The screen surface was probably our main complaint in terms of contrast, really, as the grainy texture was all too obvious to us when viewing lighter shades.

The responsiveness is of course something that can make or break a ‘gaming monitor’. AMD FreeSync worked exactly as you’d hope on this monitor, eliminating stuttering and tearing from frame and refresh rate mismatches by synchronising both factors. On a hardware level the implementation was quite impressive as the range was somewhat higher than many FreeSync models offer – 30 – 144Hz. Below this LFC (‘Low Framerate Compensation’) also came into play, although neither this nor FreeSync in general can overcome the obvious sluggish feeling and obvious perceived blur brought about by low frame rates. FreeSync aside, the monitor provided low levels of input lag and made good use of the 144Hz refresh rate in terms of ‘connected feel’. Visually things were pretty good as well, with a fairly low level of perceived blur due to the high refresh rate and generally rapid pixel responses. There were some noticeable weaknesses in terms of pixel responsiveness, however. This added to the perceived blur and provided some trailing in places that ideally wouldn’t be there – on the plus side, there was no obvious overshoot when using the optimal ‘Overdrive’ setting.

So as is often the case when you analyse a monitor in as much depth as we to, there are distinct strengths and weaknesses. The monitor is certainly capable of providing an enjoyable gaming and ‘general purpose’ computing experience. But we can’t help feeling slightly disappointed by the choice of screen surface (or specifically, the panel choice with that particular attribute) and to an extent the pixel responsiveness. Looking beyond the mixed performance, the physical product itself was quite impressive in terms of its sturdy construction and in our view fairly modest styling. The included stand offers strong ergonomic flexibility and is strikingly sturdy (and heavy), keeping the monitor firmly rooted in place whilst you adjust it. We always like to see metal used in place of plastic for things like this, so kudos to AOC in that respect. The OSD remote, flick-down headphone jack and fairly generous port selection are also worth noting.

The bottom line; an interesting addition to the 24” gaming monitor space, with a nice pixel density and some good gaming features – let down a bit by the screen surface and pixel responsiveness.

 

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