ViewSonic XG2530

Responsiveness

Input lag

A sensitive camera and a utility called SMTT 2.0 was used to assess the input lag of the XG2530. It was compared with a number of monitors of known latency, with over 30 repeat readings taken to try to maximise accuracy. Using this method we calculated 8.67ms (~ 2 frames at 240Hz) of input lag. This was with the monitor set up as per our test settings. Bear in mind that this value takes into account both the element of input lag you ‘see’ (pixel responsiveness) and the element you ‘feel’ (signal delay). It indicates a fairly low (but not ‘super low’) signal delay that shouldn’t bother most users, but that some sensitive users could take issue with. We have no way to accurately measure input lag when FreeSync is doing its thing.

Perceived blur (pursuit photography)

Our responsiveness article takes a detailed look at factors which affect responsiveness of a monitor. Chief amongst these is the concept of ‘perceived blur’, which the pixel responsiveness of the monitor is generally the more minor contributor to. The movement of your eyes as you track motion on the screen is generally a far more prominent contributing factor on modern monitors. Both aspects of perceived blur can be accurately captured using a photography technique explored in the article; ‘pursuit photography’. This uses a moving camera rather than a static one to capture a snapshot of motion on the screen, giving a good idea of what the eye actually sees at that given moment in time when observing motion on the screen.

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 practical speed to take such photographs at and demonstrates both attributes of perceived blur nicely. The UFOs move across the screen from left to right at a frame rate matching the refresh rate of the display. Three sets of photos are included, with the monitor set to 60Hz, 144Hz and 240Hz, respectively. All three rows of the test (dark, medium and light background) are used to showcase a range of different pixel transitions. All of the ‘Rampage Response’ (pixel overdrive) settings of the monitor are tested – this can be selected in the ‘CUSTOM’ presets as noted earlier. For 60Hz and 144Hz a capture from a reference monitor is shown, namely the Dell S2417DG, giving an indication of what things look like without pixel responsiveness really being a limiting factor. As this is the first 240Hz model we’ve reviewed, there is no 240Hz reference to compare to.

The images above were captured with the monitor set to 60Hz. You can see that the object itself is quite soft and broad with blurred details. This indicates a moderate degree of perceived blur attributable to camera (eye) movement. There are also varying degrees of trailing behind the object caused by the pixel responses of the monitor. With the ‘Standard’ setting there is quite a bit of trailing behind the object, most noticeably for the dark and medium background. The ‘Fast’ setting increases the pixel overdrive effectiveness quite considerably, cutting down on this trailing significantly. The ‘Faster’ setting knocks things up another notch, reducing the trailing further so that it is barely visible. The ‘Ultra Fast’ setting provides a level of acceleration that is a bit too high, at this refresh rate. You can see noticeable inverse ghosting (overshoot) introduced for the medium background in particular – a bright blue trail is visible behind the object that does not blend in neatly. The ‘Fastest’ setting increases this overshoot and makes it somewhat more noticeable for the light background as well.

With the refresh rate increased to 144Hz, as shown above, the perceived blur is massively reduced. You can see that the object itself is significantly narrower, with some sharper details visible on the UFO itself. The trailing has also changed in nature quite considerably. With the ‘Standard’ setting there is a bit of trailing behind the object, although this is quite faint compared to at 60Hz. The ‘Fast’ setting cuts this down a bit, although a very small amount remains. The ‘Faster’ setting makes very subtle changes, introducing a tiny trace of overshoot to the medium background. With the ‘Ultra Fast’ setting, this overshoot is increased slightly, but it replaces the small amount of conventional trailing that remained for the medium background. Some overshoot is also introduced for the dark background and a very small amount for the light background. The ‘Fastest’ setting further increases the overshoot levels for all backgrounds but does not introduce noticeable benefits here.

Ramping up to 240Hz provides a further significant reduction in perceived blur, as shown above. The UFO is now sharply focussed, with good details visible on the body itself – this indicates a relatively low level of perceived blur attributable to camera (eye) movement. The trailing is now very short with differences between the transitions and ‘Rampage Response’ settings a lot less noticeable than at lower refresh rates. The middle row shows the changes most clearly, with ‘Standard’ showing a fair amount of conventional trailing behind the object. It appears subtle on this snapshot, but in practice it does significantly affect the perceived blur when gaming or viewing other moving content. The ‘Fast’ setting cuts this down quite substantially, with the ‘Faster’ setting offering only slight improvement here. The small amount of trailing for the light background is perhaps he most noticeable change, although even this is a subtle change. The ‘Ultra Fast’ setting again makes only slight changes to these transitions. There is a small amount of overshoot visible for the medium background, behind the lower region of the UFO cockpit. The ‘Fastest’ setting doesn’t really make any notable changes here.

We appreciate there is a lot to take in from this assessment using TestUFO, but even then it is by no means a complete test. There are many more transitions between many different shade levels that are not assessed here, but which will crop up when gaming on the monitor. The pursuit photography shots clearly demonstrate significant reduction in perceived blur when increasing refresh rate. They also demonstrate that differences between the ‘Rampage Response’ settings become less pronounced at higher refresh rate. In practice we found the default ‘Faster’ setting quite well balanced, but there were some transitions that we felt ‘Ultra Fast’ gave a bit of an edge to at 240Hz. There was a small amount of additional overshoot (inverse ghosting) in places when using this setting, but we felt this was outweighed by the reduction in perceived blur elsewhere. This would definitely be something users should set according to preferences, but for our subjective testing below we set ‘Rampage Response’ to ‘Ultra Fast’.

Note: We observed significant stuttering on ‘Test UFO’ when we changed presets on the monitor or changed other settings that caused the monitor to reactivate its signal (i.e. turn off briefly then back on) at 240Hz. This was removed by turning the monitor off then back on again using the power button and only affected this test – there was no frame skipping observed, so it seemed to be some sort of sync error linked to the web browser. Note that the monitor worked correctly at up to 240Hz without skipping frames and displayed similar response behaviour on our Nvidia GTX 1070. In fact we performed the subjective testing below on both GPUs and made similar observations.

Responsiveness in games and movies

On Battlefield 1 (BF1), where the frame rate kept pace with the 240Hz refresh rate, the experience was exceptionally fluid. Although signal delay also affects how gaming on a monitor feels, to some people more than others, actually driving a 240Hz at suitably high frame rates gives a real edge in ‘connected feel’ as well. By delivering up to 4 times as much information every second as a 60Hz monitor and up to ~1.67 times as much as a 144Hz monitor, you sort of feel that bit closer to the game world as you interact with it. The other advantage of the monitor pumping out all of this information is the significant decrease in perceived blur, which is especially true when coupled with the sort of snappy pixel responses that the XG2530 demonstrates. The game world had a superb edge in sharpness and detail levels when moving around in it, especially noticeable at higher movement speeds, when compared to even the fastest 60Hz LCDs. The edge over a fast ~144Hz model was not as monumental but still noticeable. As with everything this is subjective and some users wouldn’t notice it as readily. We don’t feel it improved our performance on BF1 from a competitive point of view, but we did feel it was somewhat easier to focus on the action. And for competitive gamers playing fast-paced games, this could certainly give them an edge.

So the general high frame rate and high refresh rate experience was very positive in terms of responsiveness. And this was thanks to the pixel responsiveness doing a really nice job at 240Hz, overall. There were some minor weaknesses if we looked out for them, but we really did have to look out for them as they did not jump out of us when just playing the game normally. There was a tiny bit of additional trailing for some transitions, such as those between very dark and very light shades but also some dark to medium transitions. Dark silhouetted trees against an overcast sky, for example, had a faint powdery trail behind them. For scenes involving very light shades in the background and thinner objects of medium or dark shades, there was a mild pink fringe to the trail. For example, a dark vehicle aerial moving against bright clouds. This was actually something that was easier to notice on the desktop with black text against a white background but even then didn’t make us want to claw our eyes out. It occurred regardless of the ‘Rampage Response’ setting and seems to be a slight native weakness of the panel. We didn’t notice any obvious overshoot, just a few traces of darker or partially transparent (slightly lighter) trails than the foreground or background colour. We didn’t find any of these weaknesses eye-catching and most users would probably need them specifically pointed out to notice them; we’re just mentioning this for completeness.

Given the depth of analysis on BF1 above, we don’t have a lot to add about the experience on Dirt Rally. We didn’t find the increase in ‘connected feel’ compared to models with lower refresh rates to be particularly advantageous to us. Certainly not compared to on titles with character movement, such as BF1. This says more about the level at which we play the game (i.e. very low) – we could still notice a difference and could see how hardcore racing fans could benefit from the increased frame rate and refresh rated. Provided their system can hack it without them lowering the graphics settings so much that the game looks like a racing game from decades past, of course. We found the lower levels of perceived blur more noticeable, when compared to models with lower refresh rates. We again found the step up from 60Hz to 144Hz more rewarding than from 144Hz to 240Hz, but did still notice and appreciate the difference. The pixel responsiveness was clearly good enough to deliver a decent 240Hz performance, with the same sort of minor weaknesses (i.e. non-issues for most mere mortals) mentioned previously. These weaknesses didn’t significantly affect the overall level of perceived blur, which is a point reinforced by our recently updated responsiveness article. Our testing there confirms our subjective testing here; the monitor delivers a solid 240Hz performance in terms of perceived blur.

We also tested our Blu-ray test titles. These run at ~24fps and therefore do not benefit from the snappy pixel responses nor the high frame rates that this model can display. That low frame rate limits the fluidity but also the pixel response requirements of the display for an ‘optimal viewing experience’. There were no weaknesses we could see related to pixel responsiveness. Because 24fps divides evenly into 240Hz, though, there was a bit of a reduction in juddering when compared to running on models without such a neat matching. This includes 144Hz models, which is why people sensitive to such things may prefer to watch such movies at 120Hz or another refresh rate matching or equally dividing into 24. 60fps movie content also divides nicely into 240Hz, of course. You can also run this model at 23Hz or 24Hz if you prefer the refresh rate to match your lower frame rate movie content exactly.

Interlace pattern artifacts

Some models exhibit what we refer to as ‘interlace pattern artifacts’, particularly but by no means exclusively those with high refresh rates. These artifacts can also be referred to as ‘inversion artifacts’ or ‘scan lines’. Sometimes static interlacing patterns are visible, whereby shades are broken up into thin (usually vertical) lines that alternate between a slightly lighter and slightly darker than intended variant of the shade. Dynamic interlacing patterns may also be observed, which take many forms and sometimes appear as a sort of mesh, grid or lines or ‘interference’ when you observe motion on the monitor.

The XG2530 did not exhibit any noticeable static interlace pattern artifacts, but did exhibit dynamic interlace patterns. If you observed movement on the screen, you could see the image appear to break up into a vertical pinstripe sort of effect. Although we noticed this, we didn’t find it distracting and soon forgot about it when absorbed in a game. This was the case at higher refresh rates, at least. At 60Hz the monitor suffered from very obvious dynamic interlace patterns. These even seemed to move on their own accord without your eyes scanning the screen and really stood out in quite a major way to us. How obvious a user would find these depends on the viewing distance, their eyesight and sensitivity to such things. But we did find the effect surprisingly pronounced at 60Hz, much less so (but still there) at higher refresh rates. Note that the ‘Rampage Response’ setting did not affect this.

FreeSync – the technology and activating it

AMD FreeSync is a variable refresh rate technology, the red team’s alterative to Nvidia G-SYNC. Both of these articles explore the principles behind variable refresh rate technologies and the benefits that they bring to the experience, so we won’t be repeating too much of that here. The basic principle is that the monitor dynamically adjusts its refresh rate to match the frame rate being outputted by the GPU, where possible. This avoids the stuttering (VSync on) or tearing and juddering (VSync off) that is associated with refresh rate and frame rate mismatches. In the variable frame rate environment under which the technology is active, FreeSync also promises decreased latency compared to running with VSync enabled.

FreeSync requires a compatible AMD GPU, which our test system had in the form of a Club3D Radeon R9 290 royalAce. A list of current GPUs which support the technology can be here, with the expectation that future AMD GPUs will support the feature too. The monitor itself must also support ‘VESA Adaptive-Sync’ for FreeSync to be usable. The XG2530 supports this via DP 1.2a only. AMD’s recent drivers include Radeon Software Crimson, which makes activation of the technology very straightforward. So straightforward, in fact, that it should be enabled automatically. 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.



If you don’t see this option and you have a FreeSync compatible GPU, make sure that ‘AMD FreeSync’ is set set to ‘On’ in the ‘Gaming Settings’ section of the monitor OSD. If the option still isn’t there, try reinstalling the graphics driver. The ViewSonic supports a variable refresh rate range of 48 – 240Hz. That means that if the game is running between 48fps and 240fps, the monitor dynamically adjusts its refresh rate to match the frame rate. When the frame rate rises above 240fps, the monitor will stay at 240Hz 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 240fps, 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 >240fps). 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. Say for example a game was running at 29fps, the monitor would set itself to 58Hz to keep tearing and stuttering at bay. LFC is used regardless of the VSync setting – so the VSync setting only makes a difference above the ceiling of operation (240fps in this case).

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 activate if you enable it within the game itself, if such an option exists. This option may be called ‘sync every frame’ or something similar rather than just ‘VSync’.



There are a couple of final points to note. 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. As noted on the OSD video, there is an indication that this is working under ‘Setup Menu – Information’ Check for fluctuations in the vertical frequency listed here that correspond to frame rate fluctuations.

FreeSync – the experience

We tested a range of game titles to see FreeSync in action on the XG2530, but it worked in much the same way on all of them (as you would hope). We will therefore simply be focusing on a single title for this section; Battlefield 1 (BF1). Given the flexibility in the graphics options, it’s possible to test a huge range of refresh rates (in-game frame rates) on this game. It was actually very difficult to maintain a solid 240fps with the Radeon 290 (a little easier but still challenging on our GTX 1070). Even when putting the graphics settings as low as they would go, including lowering resolution scale (rendering resolution) or indeed dropping the actual resolution, this was the case. At this point you really become limited by other components in the system, such as the CPU. Even if the frame rate rarely stuck at 240fps, using fairly low settings and the native Full HD resolution (no resolution scale adjustment), it did generally stay above 200fps. FreeSync therefore did its thing to ensure that the monitor’s refresh rate dynamically adjusted below its maximum 240Hz to match the frame rate. In doing so it removed the stuttering (VSync on) or tearing and juddering (VSync on) that exists with the technology disabled.

At such high frame rates we actually found the effects of ‘tearing and juddering’ (VSync off) to be quite tolerable. Stuttering (VSync on) somewhat less so, but still far less jarring than at lower frame rates. So whilst we enjoyed the benefits that FreeSync brought, we really don’t feel the technology is so much of a game-changer at such high frame rates. You didn’t get eye-catching tear lines and the game still looked and felt rather smooth – although there was some juddering as different sections of the screen simultaneously displayed different frames. Sensitivity to tearing, stuttering and juddering does vary, but we feel the benefits of FreeSync are far less pronounced at these frame rates.

If we increased the graphics settings so that the frame rate dipped below 200fps, but generally still stayed in the triple digits (i.e. 100 – 200Hz for the monitor refresh rate) we found the benefits of FreeSync more pronounced. The fluctuations in frame rate and the associated tearing and stuttering we found quite unpleasant at this sort of frame rate range, so it was certainly nice to have that eliminated. Compared to the higher frame rates (ideally 240fps) and corresponding refresh rates, there was an increase in perceived blur and a bit of a decrease in connected feel. The frame rate itself dictates this and FreeSync can’t make a relatively low frame rate higher than it actually is. Even so, we felt that the connected feel and perceived blur levels remained pleasing, particularly at the mid-high end of this frame rate range.

Increasing the graphics settings further yielded a further increase in perceived blur and decrease in perceived blur, due to the resulting decrease in frame rate. Looking back and comparing this to the other end of the scale (i.e. the frame rates closer to 240fps), the difference in these two elements was really rather profound. Although FreeSync didn’t change this, it did indeed work its magic to rid the experience of tearing and stuttering associated with refresh rate and frame rate mismatches. And at these sorts of frame rates, such imperfections are much easier to notice than at significantly higher frame rates. As the frame rate fell, particularly as it dropped below 80fps, more noticeable overshoot was introduced. Fortunately, the pixel overdrive feature of the monitor (‘Rampage Response’) is very flexible and sticking with the default of ‘Faster’ rather than ‘Ultra Fast’ kept the overshoot levels quite low. We’d suggest ‘Ultra Fast’ only if your frame rate spends most of the time closer to the upper end of the FreeSync range, above 200fps really. If your frame rate spends most of its time below 100fps then ‘Faster’ is more appropriate. We did not observe the more noticeable interlace pattern artifacts that we saw at a static 60Hz, even when the frame rate (and hence refresh rate) hovered around this.

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.

Conclusion

With its 240Hz refresh rate, the ViewSonic XG2530 is clearly designed for speed. But whilst this remained a key focus for the model, it doesn’t nullify the importance of other attributes such as contrast and colour reproduction. The contrast was much in line with other TN models we’ve tested recently, despite the contrast on our unit falling slightly short of the specified 1000:1 static contrast ratio. There was no ‘IPS glow’ or anything of that nature, naturally, but perceived gamma was dependent on viewing position. From a normal viewing position, this affected detail in dark scenes depending on which part of the screen you’re observing. The screen surface also had a bit of a grainy quality to it, which as with contrast characteristics was in line with expectation from our testing of comparable models.

Colour reproduction was quite decent, within the constraints of the TN panel technology. The perceived gamma differences again game into play here, giving the image a deeper and more saturated look than intended towards the top of the screen. Towards the bottom of the screen, some saturation was lost and things appeared more muted. Unlike many high refresh rate TN models, though, the default image setup was actually quite pleasing. The monitor didn’t suffer from the plague of low average gamma that affects many of these models, meaning that it achieved a fairly rich look without requiring the intervention of ICC profiles. Furthermore, gamma was adjustable alongside a plethora of other settings the OSD. In fact this model had one of the most feature-rich OSDs we’ve seen for a while. Our unit also offered quite good white point balance out of the box, which was good to see.

Responsiveness was very impressive overall, with the vast majority of pixel responses being snappy enough to support output at up to 240Hz (@240fps) without issue. The monitor achieved exceptionally low levels of perceived blur, superior to comparable 144Hz models. There were some minor weaknesses in pixel responsiveness here and there, alongside a small amount of overshoot, but nothing we found bothersome. The monitor also supported FreeSync well, with the technology getting rid of tearing and stuttering by keeping the refresh rate of the monitor synchronised with the frame rate outputted by the GPU. This worked across a very broad range of refresh rates, with LFC kicking in as intended and extending this below the 48Hz hardware floor of operation. A bit of a bugbear for some users is input lag. That was low on this model and shouldn’t present an issue to most users. However; it is not ‘extremely low’ and there is a slight signal delay that sensitive users could take issue with.

Overall, then, the monitor performed largely as well as one could hope given the panel used. The monitor was nicely set up out of the box, offered excellent OSD flexibility as well as the sort of ergonomic flexibility many have come to expect from this class of monitor. There were no particularly eye-catching ‘gaming’ fashion statements externally, either, just a few red elements that blended in with the overall design quite well. Responsiveness was excellent overall, despite a signal delay that some sensitive users could take issue with. This is a monitor that many competitive and indeed non-competitive gamers would have a blast using. To make the most of it, though, you do need to be pushing very high frame rates. Whether gaming or otherwise you’re also restricted to a 1920 x 1080 (Full HD) maximum resolution. Quite a premium is put on the 240Hz refresh rate, with the product being pretty expensive for a Full HD TN panel.

The bottom line; a very responsive monitor for both AMD and Nvidia users without any nasty image quality surprises – but the cost and slight signal delay could put some users off.

 

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