BenQ XL2730Z (ZOWIE XL2730)

Responsiveness

Input lag

We calculated input lag using a utility called SMTT 2.0. This is used alongside a sensitive camera to compare the latency of the XL2730Z (ZOWIE XL2730) with a range of monitors where the latency is known. Using this method we calculated 3.3ms (<0.5 frames at 144Hz) of input lag. The pixel response time (element you ‘see’) and signal delay (element you ‘feel’) both affect this value. This indicates an exceptionally low signal delay for the monitor, contributing to a very fluid and connected feel when gaming with it. ‘Blur Reduction’ did not have a significant influence on the values recorded here. We do not have the means to accurately analyse input lag with ‘FreeSync’ enabled, but as we explore the connected feel in this mode in a variable refresh rate environment is excellent. Furthermore, both AMD and BenQ have confirmed that FreeSync does not impact the signal delay of the monitor and therefore does not have a negative effect on the monitor’s input lag.

Perceived blur (pursuit photography)

In this article we explore the concept of perceived blur and how it is influenced not only by the pixel responsiveness of the monitor but also the movement of our own eyes. We then go on to introduce the concept of ‘pursuit photography’, which can capture both of these aspects. This contrasts with the usual static photography that we’ve used in reviews up until now that will only show the influence of pixel responsiveness. Using the pursuit photography method described in the article, just prior to the conclusion, we captured the images below. The middle row (medium cyan background) for the UFO Motion Test for ghosting was used with the test running at 960 pixels per second with the UFO moving across the screen from left to right. The ‘reference screen’ shown in the final column is a Samsung S27A750D set to full brightness and to a response time mode that provides optimal pixel responsiveness for each refresh rate, as noted in the article. The remaining images are all taken from the XL2730Z (ZOWIE XL2730), set to a range of different AMA (Advanced Motion Acceleration) response time settings and with ‘Blur Reduction’ enabled for the last two rows of the image.

The ‘Blur Reduction’ mode is a strobe backlight feature designed to significantly reduce eye movement and hence reduce perceived blur. This is actually ‘Blur Reduction 2.0’ which provides two adjustment options that weren’t available through the OSD of the original ‘Z’ series models. There is ‘Intensity’ which adjusts the ‘on’ period of the strobe so that the image is brighter at the expense of motion clarity (longer ‘on’ period) or dimmer with further improved motion clarity (shorter ‘on’ period). There is also an ‘Area’ setting which changes where on the screen strobe crosstalk will appear. We were happy to use the factory defaults for our testing.

At 60Hz, shown in the top row, you can see a relatively high level of blur. This is largely accounted by eye movement, as illustrated by the reference screen where this is the only real influence. If you compare the reference with ‘AMA = Off’ you can see a moderate degree of additional ‘blur’, which is actually trailing caused by slower than optimal pixel response times. With ‘AMA = High’ the pixel responses are sped up so that this is largely eliminated and things look more like the reference. There is a faint hint of overshoot (inverse ghosting) with a slight shadow behind the UFO. With ‘AMA = Premium’ very heavy acceleration is used, introducing obvious overshoot which is visible here as an inky trail behind the UFO cockpit and a halo (bright) trail behind the UFO body.

At 120Hz, shown in the second row, there is a significant reduction in perceived blur. The reference screen shows this very nicely, with no noticeable trailing and very little overshoot – again, perceived blur from eye movement is the key factor here. With ‘AMA = Off’ you can see that the UFO itself is sharper and the details within it (such as the alien) appear less elongated. There is some trailing behind it, though, which is due to slower than optimal pixel responses. With ‘AMA = High’ the conventional trailing is as good as eliminated and things look closer to the reference. There is a bit of a ‘vapour trail’ behind the object which is a bit of overshoot. With ‘AMA = Premium’ there is obvious overshoot, with a bold inverted trail accompanying the UFO. At 144Hz, shown in the third row, things are really very similar to at 120Hz. There is no 144Hz reference here as the reference screen is limited to a 120Hz refresh rate. You only gain an extra 24fps and therefore the potential improvement in perceived blur is extremely limited, especially when comparing 60Hz to 120Hz. When using the monitor outside of this test we actually found the slight increase in ‘connectedness’ (i.e. how things ‘felt’) to be a small but noticeable improvement, whereas by way of motion blur things were very similar as shown here.

The fourth and fifth rows show the results with the monitor set to strobe at 120Hz and 144Hz, respectively. If you look at the reference image, with the S27A750D set to its ‘Frame Sequential’ mode and strobing at its maximum 120Hz refresh rate, you can see that the main object (UFO) is extremely clear. You can see a level of clarity and detail on its features that is far beyond what can be seen previously where the backlight does not strobe. There is a fairly faint trail behind this as a result of slightly slower than optimal pixel transitions. On the BenQ you can see that the main image maintains this exceptional clarity and detail level. With ‘AMA = Off’ there is some conventional trailing due to slower than optimal pixel transitions, with a moderate primary and even faint secondary trail. ‘AMA = High’ replaces these trails with some inverse ghosting, which is intensified using the ‘AMA = Premium’ setting. Note that adjusting the ‘Intensity’ or ‘Area’ settings did little to improve this inverse ghosting. In practice, as we explore later, the inverse ghosting with ‘AMA = High’ and Blur Reduction enabled was not at all obvious, whereas the potential clarity of objects during motion was. Again 120Hz and 144Hz provided similar performance really, with what you ‘feel’ rather than what you ‘see’ perhaps being the main change. Albeit still a minor one. It does appear from these images that ‘120Hz Strobe’ is clearer than ‘144Hz Strobe’, but that is simply because the photographs themselves are better (clearer).

We would like to end this section with a bit of an aside, by talking a little bit about ‘interlace-pattern artifacts’. We do not intend to go into any technical detail about these, but they are related to imperfections in the voltage control of the monitor during pixel transitions. They are very common on high refresh rate monitors in particular and do indeed occur on this one. They manifest as a faint vertical interlaced (interleaved) pattern during motion on the monitor. They can be seen in the image below, which shows a pistol recoiling upwards on Battlefield Hardline. Notice the vertical green lines on the ‘enhanced iron sights’ of the weapon. Please click to enlarge the image, otherwise the lines blend in.

You can also see them in the image below when it is enlarged. This shows a neon sign on Battlefield Hardline with the mouse moved from the bottom to top of the sign at a moderate pace. Obviously you don’t see this distinct ghost image with interlacing trailing behind the main object, but you can see the interlacing effect demonstrated here if you have a keen eye.

Please note that these artifacts don’t occur during transitions between all shades, they are generally found where fairly bright shades are involved. More importantly, they are not something that most users would actually notice. We were almost reluctant to bring these up as we don’t think most users should worry about them at all, but for the sake of completeness we thought they should be mentioned.

Responsiveness in games and movies

On BF4 the experience was very fluid where the frame rate matched the 144Hz refresh rate of the monitor. You felt really connected to the game, with the monitor seeming to respond instantaneously to your inputs. The pixel responses were clearly very snappy indeed, able to make full use of the refresh rate without any conventional trailing. The level of motion blur was very low, as you’d hope for from the refresh rate. This made it that bit easier to keep track of enemies when moving rapidly on foot or in a vehicle compared to LCDs with lower refresh rates. There was a downside to these very rapid pixel transitions, though, and that is that very ‘aggressive’ pixel overdrive is used. There was some overshoot in places, but this was generally rather light and not too obtrusive in our opinion. There was a fairly faint and short transparent (‘snail slime’) trail next to some objects, for example vehicles and buildings as you moved past them with light blue sky in the background. This didn’t generally catch the eye and was something we had to look out for. If the object was lighter, for example a white painted wall with deep blue sky in the background, the trail became a somewhat more noticeable dark grey. Not everyone will notice this inverse ghosting, but it is something that some users are sensitive to and may be bothered by. We didn’t find it as bold as on previous XL Series monitors we’ve tested, which is good.

As the frame rate dropped below this or rose above it, tearing ensued. To sensitive eyes such as ours, this was quite obvious – even if the distinct tear lines aren’t visible, it has the effect of objects appearing to ‘judder’ rather than move smoothly. With VSync enabled there was obvious stuttering if the frame rate fell even slightly below the refresh rate, which really hampered the ‘connected feel’ of the game. The level of motion blur also increased in proportion to a decrease in frame rate, as you would expect. With ‘Blur Reduction’ (BR) the stuttering was very pronounced indeed where the frame rate departed from the refresh rate. That is because there isn’t the same degree of motion blur to mask this juddering, so it appears rather distinct. Where the frame rate matched the refresh rate (be it 120Hz or 144Hz – we tested both) the clarity of motion was superb with BR on. The game world appeared exceptionally sharp and focused even if you moved your character rapidly, making moving in quick vehicles far less dizzying and making it surprisingly easy to keep track of enemies. The ‘connected feeling’ was definitely there as well, with 144Hz providing just a little bit of an edge here. As we explored previously, there are some fairly faint ‘staggered trails’ which can be observed during fast motion. These appeared as very faint repetitions behind certain objects as you moved quickly past them and couldn’t really be observed as staggered overshoot trails due to how faint they appeared. These were much fainter that we’ve observed on Nvidia’s similar ULMB (Ultra Low Motion Blur) strobe backlight solution and was something we actually had to actively seek out to notice. In many ways this was even less obtrusive than the overshoot that you get with Blur Reduction disabled and AMA enabled, so not even something that sensitive users should worry about really.

We also tested Dirt 3, which again benefited from the high refresh rate of the monitor. Where the frame rate and refresh rate matched (144fps at 144Hz) things were very fluid. We didn’t really gain much benefit in terms of ‘connectedness’ with the keyboard we used to control the vehicle, but the motion blur was pleasantly low. Other cars and environments racing past had a respectable degree of sharpness, allowing you to admire the scenery a bit more. Or perhaps concentrate on the road that bit better. There were no troublesome issues with overshoot either. It was certainly there here and there, but fainter and less obtrusive than on previous XL Series models.

The BR mode also did its thing on this game, but again required the frame rate to be laser-locked to the refresh rate to avoid extremely unpleasant stuttering and suchlike. The benefit of this was questionable in the regular game modes, where 144Hz already provided a nice fluid experience really. On the Gymkhana mode, though, the rapid spins could be performed without the course blurring much at all. This really helped us to focus on the obstacles, although we were still rubbish at Gymkhana regardless of that. We didn’t notice any obtrusive issues with trailing or object repetitions, either. They were there if you looked quite carefully, but were faint and unobtrusive really.

Finally we took a look at our Blu-ray movie test titles to assess the motion performance of the monitor on those. The pixel responsiveness did not hamper the experience in any way, with no additional trailing or inverse ghosting that we noticed. If you did happen to notice any inverse ghosting with ‘AMA’ set to ‘High’, you could always set this to ‘Off’ for movie watching. The ‘Off’ setting did not introduce any trailing in movies as the pixel responsiveness was good enough for this pace of action. The frame rate at which current Blu-rays currently run is limited to around 24fps and that limits the overall fluidity and pace of action. There was less ‘juddering’ as the refresh rate of the monitor (144Hz) divides evenly into 24fps, but the overall smoothness is still limited by the low source refresh rate. We didn’t find the ‘Blur Reduction’ feature added anything positive to the experience, either.

FreeSync – the technology and activating it

We have already explored Nvidia’s G-SYNC variable refresh rate technology, reviewing a range of monitors which use this. As with Nvidia G-SYNC, AMD’s FreeSync technology aims to smooth out the gaming experience in variable refresh rate environments by reducing stuttering, juddering and tearing. Synchronising the refresh rate of the monitor with the frame rate outputted by the GPU is an important part of delivering the smoothest gaming experience in the variable frame rate environments that are common in games. Note that network latency, ‘CPU spikes’ and other such issues can also affect smoothness, but these are not affected by variable refresh rate tech. We have explored the technical reasons for this in the G-SYNC article previously linked to and also in the ‘Variable refresh rate’ section of this article, so please refer to those article if you’re interested in such details.

G-SYNC requires the use of a proprietary ‘G-SYNC board’ integrated into the monitor, which replaces the traditional scaling hardware and assistive electronics of the monitor. This allows Nvidia to tightly control both the colour and responsiveness tuning of the monitor, but blocks off the other ports and many of the manufacturer-specific OSD features of the monitor. FreeSync on the other hand relies on the ‘Adaptive-Sync’ protocol, which is an optional DisplayPort 1.2a extension supported by VESA. On monitors that specifically support this (not all DP 1.2a ports do) you essentially retain all of the manufacturer-specific ‘goodies’ on the OSD as well as the full range of ports, although you must use the ‘DP 1.2a+’ port to use the Adaptive-Sync protocol and therefore make use of FreeSync. This way of doing things generally ends up cheaper to the consumer. This is especially true when considering G-SYNC models that support ports other than DisplayPort – as they contain the traditional assistive electronics and scaler in addition to the G-SYNC board.

To enable FreeSync you need both a compatible monitor, such as the BenQ XL2730Z (ZOWIE XL2730) reviewed herein, and a compatible AMD graphics card. We are using the Club3D Radeon R9 290 royalAce to run FreeSync on this model other models are compatible and most if not all future GPUs by AMD should also be fully compatible. When you first connect the monitor up and get onto Windows you’re actually presented with a notification from Catalyst Control Centre (CCC) that you’ve got a FreeSync-capable display and should enable the technology. To do this you simply open CCC and navigate to ‘My Digital Flat-Panels – Properties (Digital Flat-Panel)’, ensure the checkbox at the bottom of the page is ticked and then press ‘Apply’. This page and checkbox is shown in the image below.

There are a few important things to note which are specific to FreeSync and this monitor:

1) You may find that the checkbox isn’t there on the relevant page. If you’re running ‘Blur Reduction’, note that this disables FreeSync – you can’t use these technologies together, they can only be used separately. If you aren’t running this then try turning this feature ‘On’ and then ‘Off’ in the OSD, as that should ‘re-communicate’ the fact that you’re using a compatible display to the graphics card.

2) At least on the revision of the monitor we tested, AMA is always set to ‘off’ regardless of the setting that you select in the OSD. We explore the consequences of this in the subsequent section. Newer revisions of the monitor (‘V002’) allow the user to enable and control AMA whilst using FreeSync.

3) The operating range for FreeSync is 40-144Hz on this monitor. Outside of this range the monitor will respect your choice of ‘VSync on’ or ‘VSync off’ and behave accordingly. That means that if you have ‘VSync on’ you get stuttering if the frame rate falls below 40fps a latency penalty if it tries to rise above 144fps. With ‘Vsync off’ you get tearing/juddering below or above the limits. This is a bit different to G-SYNC which at time of writing forces VSync on in both scenarios, but can still minimise stuttering below the floor of operation by setting the refresh rate to double the frame rate. If for example the game was running at 35fps, the G-SYNC monitor would set the monitor’s refresh rate to 70Hz so that the frames divides evenly into the refresh cycle of the monitor. This is now an added feature of the new ‘Radeon Software Crimson’ suite called ‘Low Frame Rate Compensation’. Regardless of this, low frame rates are still low frame rates as we explored on our G-SYNC reviews and will explore for FreeSync below.

FreeSync – the experience

Warframe is a title which generally sits at rather high frame rates, in the triple digits but rarely consistently matching the 144Hz maximum refresh rate of the monitor. As explored previously, there is considerable stuttering or tearing (and juddering) in this sort of variable refresh rate environment. Some users seem to have this notion that the sort of issues that FreeSync sets out to solve are not noticeable at high refresh rates and frame rates. That is categorically not true. Whilst these issues are certainly less significant, they are definitely there and to users who are even moderately sensitive to them they can really affect the gaming experience. With FreeSync enabled this title was very smooth, fluid and playable in these triple-digit frame rates – free from disruptive stuttering and tearing. There were some instances where frame rate dropped rather abruptly to around 50-70fps, when the action suddenly intensified massively. This sharp drop was still a shock to the system and the game lost the fluidity and connectedness that was enjoyed at higher frame rates, in addition to motion blur increasing.

We also found the pixel responsive of the monitor to be surprisingly good on this title, overall, even though AMA was forcefully disabled. There was a little extra trailing in places due to some slower than optimal pixel transitions, particularly where bright objects (such as lights or illuminated ‘powerups’ etc.) sat surrounded by darker colours. This was never severe, though, and you could definitely still observe the benefits of hugely reduced motion blur at higher refresh rates.

The technology was also tested on GTA V, which is quite a graphically demanding title on which we like to crank up the detail settings a fair bit. With the settings we like to use the frame rate generally sits at around 50-70fps. Without FreeSync this provides significant stuttering or tearing, which sensitive eyes such as ours really dislike. Whilst the game certainly didn’t have the same low levels of motion blur and overall connectedness that you would expect from higher frame rates and refresh rates, the overall smoothness was very enjoyable. It actually made the game a lot more playable, especially when driving at high speeds. Having the experience interrupted by tearing, juddering or stuttering is not only something we found annoying on this title, it was something we feel really affected the playability. So it was great to see the back of it such interruptions.

We did of course also test our staple title, BF4. This title is well known for its fluctuating frame rates and is indeed a popular title used by both Nvidia and AMD when promoting their variable refresh rate technologies. As with Warframe this generally ran with frame rates in the triple digits, but rarely stayed at 144fps for long with the settings we enjoy using. In this relatively high but variable frame rate environment, FreeSync completely eliminated the tearing and juddering that you get with VSync off and the stuttering (and indeed latency penalty) you get with VSync on. The connectedness to the game world and overall fluidity was excellent and we definitely found the game more playable without these aforementioned interruptions. There was some very occasional stuttering, but this was generally related to network latency and not anything to do with the monitor or GPU specifically. There were some instances where frame rate dropped far lower and this again interrupted the fluidity and increased motion blur, still coming as a bit of a system shock despite the lack of stuttering or tearing. These drops were few and far between, however.

We should also mention that, as with Warframe, the level of motion blur was largely linked to eye movement and the refresh rate itself rather than being too heavily influenced by pixel responsiveness. There was again a bit of trailing beyond what you’d see with AMA set to ‘High’, particularly where darker shades such as the gunmetal greys of vehicles or dark tree bark was cast against lighter shades such as blue sky or lighter patches of earth. This was fairly constrained really and didn’t really spoil our overall appreciation of the advantages brought about by the higher refresh rates and frame rates. There was again no overshoot, either, which is a bonus that some users might appreciate more than others.

To complete our game testing we tested Dirt 3. This was more a test for the effects of having AMA forcefully set to ‘Off’ when using FreeSync rather than a test for the technology itself. That is simply because this title ran quite comfortably at 144fps (144Hz) most of the time with the settings we were happy to use. There were occasional dips a little below that, so it was nice not to suffer from stuttering as a result of this. With VSync disabled it would frequently climb above this, too, and it is nice not to have any tearing. In the way of pixel responsiveness the monitor again managed to make good use of the refresh rate (up to 144Hz), despite AMA being disabled. There was some additional trailing in places, for example when passing lightly coloured road signs with darker vegetation or another backdrop in the background. These sorts slower than optimal transitions were quite common when racing at night. Again we didn’t feel that some users would mind or indeed notice this extra trailing, and indeed there was no inverse ghosting which some users dislike even more.

Interpolation and upscaling

This monitor has a native resolution of 2560 x 1440 at which it will run with optimal clarity. If you connect a source (be it a PC GPU, games console or other device) that runs at a lower resolution, then the monitor will be able to use its integrated scaling functionality to display this. There are two key ways in which the monitor handles this, both of which are found in the ‘Display – Display Mode’ section of the OSD; ‘Full’ and ‘1:1’. The ‘Full’ option is used by default, and will force the monitor to use interpolation to display an image using all of its pixels. The ‘1:1’ option allows the monitor to use 1:1 pixel mapping, therefore displaying only the required number of pixels with the remaining pixels remaining unlit as a black border around the image. Both options can be seen in the relevant section of the OSD video, shown below for your convenience.

If you set the resolution to one that is lower than the native 2560 x 1440 (WQHD), such as 1920 x 1080 (Full HD), things appear soft if you use the ‘Full’ option. There is no wasted screen space, but you lose a moderate degree of sharpness compared to running that resolution on a native Full HD display of a similar size and with a similar screen surface. You can see this softening on the desktop quite readily and also when gaming. The edges of textures appear somewhat blurred as if a sort of anti-aliasing filter is applied. Textures lack the sharpness that they should have and the game environment generally looks quite soft. If you do want to use this monitor at resolutions that are lower than native then you will have to think carefully about whether you want this softening or whether you would like a large black border surrounding the image (1:1). With the latter option the image essentially appears as it would on a ~20” 1920 x 1080 monitor.

If you watch lower resolution content over the PC but keep the screen resolution set to 2560 x 1440, then upscaling is used. You might be watching a Blu-ray or Netflix movie with movie software or a web browser, for example. This upscaling is handled by the GPU or software itself and essentially makes the image look quite similar to on an otherwise similar screen with Full HD resolution. There is very slight softening, but this is not at all significant and much weaker than when the aforementioned interpolation process is used.

Conclusion

BenQ’s XL Series gaming monitors usually provide strong responsiveness at the expense of image quality. Regardless of the tweaking you do in the OSD, you’re left with dodgy gamma and an unbalanced image – oversaturated in some places, washed out in others. The XL2730Z (ZOWIE XL2730) was quite a refreshing change in that respect. Out of the box it was certainly an eyesore, as usual, but after a bit of tweaking quickly become well balanced. Whilst the usual TN viewing angle related inconsistencies applied, such as weakening saturation most notably towards the bottom of the screen, the overall image was rich and varied. This was complimented nicely by the 2560 x 1440 (WQHD) resolution, which is another first for the series. The screen surface didn’t provide the clarity or smoothness that you’d see on recent IPS-type models with the same resolution, though. We found setting up the monitor and indeed quickly switching between different sets of settings a breeze with the ‘S-Switch Arc’. Whilst its new design didn’t really enhance its functionality too much, we do feel it looks nicer. And the same can be said about the monitor more broadly – it is very solidly built and aesthetically speaking we found it quite appealing.

There are a lot of extra features, such as ‘Black eQualizer’ and ‘Color Vibrance’, but if you’re interested in an accurate representation of images, games and other content then it’s best to leave these alone. We certainly appreciate that the user has the flexibility to change such features through the OSD regardless of the preset mode they’re using. You can actually completely disable the ‘Black eQualizer’ and obtain accurate gamma tracking in the centre of the screen without resorting to ICC profiles or other such imperfect modifications – a real plus compared to older models in the series. As a result of this dark scenes had an atmospheric look rather than appearing flooded with strange patches of grey here and there. The overall contrast performance was quite decent, nothing spectacular but enough to provide a decent experience without any annoying issues. Except perhaps the grain of the screen surface, which we found less than ideal.

When it came to responsiveness the monitor put in a very strong performance overall. Under its normal operation it made good use of its 144Hz refresh rate, with strong grey to grey acceleration making sure those pixels were transitioning fast enough. The downside to this rapid acceleration came in the form of overshoot (inverse ghosting), although this was somewhat reduced compared to on previous XL Series models. FreeSync worked very nicely to cut out tearing, juddering and stuttering in the variable frame rate environments that are so common in games. We really enjoyed gaming with this feature, even though it cut out ‘AMA’ completely. The overall fluidity at moderately high frame rates was still very good regardless of this and some users would like the overshoot-free experience as well. If you’re prepared to forgo FreeSync you could opt for the ‘Blur Reduction’ mode instead, which again did exactly what it should. On the upside, you get a huge reduction in motion blur which can work out really nicely for some games or situations. On the downside, you need to have your framerate laser-locked to the refresh rate of the monitor – and that’s 120Hz or 144Hz as the only two useable refresh rates with this technology. A lot is also said about the ‘flicker free’ status of the monitor, too, which does not apply with this strobe backlight technology enabled.

All in all this monitor provided a very enjoyable gaming experience. It did not compromise on image quality in quite the way we’ve come to expect from such models and also provided very strong responsiveness with a range of useful features. Overall we feel this monitor has a lot to offer for the current asking price.

 

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