Asus ROG Strix XG309CM

This is a shorter format review but we have included as much of our normal testing and results as we can, especially in relevant areas for this screen. We will of course still be carrying out our normal full, detailed reviews for the most interesting, complex and exciting new screens, but using this short format helps us cover a few additional models in the meantime. An explanation of the results and figures discussed in this short format review can be found at the bottom of the page.

Key Specs and Features

• 29.5″ ultrawide screen size with flat format
• ‘Fast IPS’ technology panel
• 2560 x 1080 resolution
• 1ms G2G quoted response time
• 220Hz maximum overclocked refresh rate
• Adaptive-sync VRR, including FreeSync Premium certification
• ELMB-sync blur reduction + VRR mode
• Standard colour gamut backlight (sRGB)
• 1x DisplayPort 1.2 and 1x HDMI 2.0 connections
• USB type-C connectivity with DP Alt mode and 15W power delivery
• Built in KVM switch
• Adjustable stand with tilt, height and swivel adjustments
• Integrated 2x 2W speakers

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Introduction

The XG309CM is the latest model in Asus’ popular mid-tier ROG Strix gaming line-up of displays. It offers a new size and resolution for the market being 29.5″ in size (classed as 30″) and offering an ultrawide aspect ratio, approximately 21:9 and a 2560 x 1080 resolution. It’s promoted by Asus as a gaming monitor “designed for professional gamers and immersive gameplay” according to their product page, while also sporting a range of extras like USB type-C connectivity and a KVM switch that make it an interesting option for work as well.

There is of course a focus on some modern gaming capabilities, with Asus touting the ever present 1ms G2G response time thanks to the use of a so-called ‘Fast IPS’ panel from AU Optronics. The use of an IPS-type panel will provide solid all round image quality and wide viewing angles that we are used to from this tech. More importantly the screen offers a high refresh rate with 200Hz native, and up to 220Hz via an overclocking feature. This is supported by adaptive-sync for variable refresh rates (VRR) from both NVIDIA and AMD systems. The screen has already been certified under the AMD ‘FreeSync Premium’ scheme, and Asus say on their product page that NVIDIA ‘G-sync Compatible’ certification is under way. Asus have also added their ‘ELMB-sync’ technology to this screen, offering a blur reduction mode that can be used at the same time as VRR. There is also the usual range of gaming settings and extras in the menu to play with.

The screen has a 3 side borderless design with a thin black plastic bezel (1.5mm) along the sides and top, then an additional 6.5mm black panel border before the image starts. The bottom edge of the screen has a thicker ~20mm black plastic bezel. The back of the screen is encased in a matte black plastic as shown above, with the stand connecting centrally. This stand is large and chunky, and finished in a matte black plastic as well. It has a familiar 3-pronged foot which provides a nice stable base for the screen. The stand provides tilt, height and swivel adjustments, all of which are smooth and easy to use. There is very little wobble from the screen as well, and it feels stable on the stand as you move it around or use the OSD menu. Although the screen does seem to have a slight alignment issue, rocking up and down a little as if it had a rotate adjustment (it doesn’t). This can be a little annoying when using the OSD controller which is located on the bottom right hand edge of the screen, causing you to move the screen a bit each time.

Speaking of the OSD menu, this is controlled through a handy joystick. We found this a bit inconvenient as we’re used to finding these controllers in the centre of the screen, which actually would have been better to avoid that slight wobble we observed when using it to the right hand side. The menu software is familiar from other Asus screens and provides a wide range of settings and options. Navigation is quick and intuitive thanks to the joystick.

The XG309CM has a few productivity enhancement features too. There is USB type-C connectivity to go along with the 1x DisplayPort 1.2 and 1x HDMI 2.0 connections which allows for single cable connectivity from supporting laptops etc. This USB type-C includes 15W power delivery (pretty modest) and DisplayPort Alt mode for video. There are also 2x USB 3.2 data ports and a headphone jack for audio. We should say here that the connections are particularly hard to get at on this screen, with a fairly limited maximum height adjustment, and the ports tucked quite far in to the back of the screen. They weren’t the easiest to plug in or access. The screen does also feature built-in 2x 2W speakers for some basic audio. Where multiple inputs are used from different sources, you can also use the screen as a KVM switch which might be handy.

The top of the stand features a ¼-inch tripod socket which allows users to mount a camera or additional display for a unique gaming or streaming setup.

Of course it wouldn’t be a gaming screen without some form of RGB lighting today, and Asus provide a logo projection on the bottom of the screen that shines on to the surface of your desk. The colour and patterns of this can be customised in the OSD or it supports Asus’ Aura Sync as well.

Setup and Colour Performance

A summary of the XG309CM setup and colour features and performance is included here for quick reference, but is discussed in a lot more detail below. Note here there is a flicker free backlight with a decent brightness adjustment available offering a good low luminance of ~50 cd/m², and a decent enough maximum of ~349 cd/m².

Default Setup

Out of the box the screen comes in the ‘Racing’ preset mode which is oddly the default for all recent Asus screens we’ve tested. Why racing, is that a particularly common gaming niche?! Anyway, the brightness was set at a modest level being not too bright for normal room conditions but likely to need turning down a tad still. The colour balance felt good, not too warm or cool, and you could tell that the screen was using a smaller colour gamut than many other displays we’ve tested in recent times. Colours looked far less saturated and vivid than most modern wide gamut screens we test.

The default gamma was largely very close to the 2.2 target, being a little high in the darker grey shades which results in a little crushing of those darker grey shades and some shadow detail loss. This is likely linked to the fairly mediocre contrast ratio of the panel which was measured at 832:1, being below the 1000:1 spec and a little disappointing for a modern IPS-type panel. The RGB balance was very good though, and this resulted in a very good colour temp, basically spot on average across the greyscale at 6491k (0% deviance from our target). The white point was ever so slightly too warm at 6424k (1% deviance), but very close to our target of 6500k. This resulted in an accurate greyscale, with low average dE of only 1.2 which was very good.

The Asus spec states a 110% sRGB colour gamut coverage, which indicates straight away that this is basically a standard gamut only. In fact we measured in our testing a relative coverage of a little lower at 104.7%, so that’s even closer to the sRGB space than the spec suggested. That extra 5 – 10% is irrelevant for any real use, and so actually it’s better that this is closer to the sRGB colour space anyway, helping to ensure that SDR content is more accurate. The absolute coverage of the sRGB space was measured here at 98.5% as well which was good. You can see from the CIE diagram on the left that the monitors colour space extends slightly beyond the sRGB space in green shades (leading to that small >100% relative coverage measurement), and falls slightly short in red shades (leading to the <100% absolute coverage measurement).

Because the screen is a standard gamut model with colours basically matching the sRGB reference space, when checking the accuracy of those produced colours the results were mostly good in this mode. We had an average dE of 2.2, but a few shades like red showed higher errors – that’s because the monitor can’t quite cover that full 100% red colour of the sRGB colour space as we said a moment ago.

Being a standard gamut only screen you do of course miss the more vivid and saturated colours that some people like for gaming and multimedia, even if they might not be “accurate”. This will also make HDR content playback more limited, as you lack the colour enhancements associated with that. It also precludes you from being able to work in wider gamut colour spaces such as Adobe RGB or DCI-P3 for colour critical/photo work too. Some people might not be bothered by this anyway, but just keep in mind this is a more traditional standard gamut-only monitor.

sRGB Mode and Factory Calibration

The XG309CM also comes factory calibrated in the separate ‘sRGB’ preset mode, which also carries a tighter emulation of the sRGB colour space in fact. A calibration report is provided with each screen as shown above for our sample, confirming a calibration to 2.2 gamma target (2.23 achieved here for our sample according to the report), 6500k colour temp and a dE <2 (0.52 achieved here apparently). We took measurements in this mode as well as shown below:

The gamma curve was actually set to sRGB here, as opposed to 2.2 as indicated on the calibration report. You can see the tapering off as you get near to black, but otherwise the curve is very similar to 2.2 anyway so that’s no issue. We had the same slightly too high gamma in the darker grey shades leading to a little loss of shadow detail. Colour temp and white point were basically spot on with a very good RGB balance across the greyscale too which was excellent. This again resulted in a strong greyscale accuracy with dE 1.4 average. Again the contrast ratio was a bit disappointing in this mode at 807:1 and confirms the panel seems to struggle a bit in this area.

This sRGB preset mode actually restricts the colour space a little more than the native mode, cutting out the slight ~105% relative over-coverage we had before and trying to more closely map to sRGB. This removes the slight over-saturation in greens which is good news, although it cuts things back a little too much and we now have an absolute coverage of 96.4%, instead of the 98.5% possible from the native backlight. Nothing major, and we’d still consider this a good coverage of sRGB. Thankfully you still have access to the brightness control in this mode, allowing you to adjust the brightness to your requirements and room conditions, unlike quite a lot of screens where this mode gets fully locked down and makes it unusable. There is also access to the gamma control, but not the colour temp / RGB settings, not that those are needed with a very accurate colour temp setup here at 6500k. With the factory calibration in play, we had very good overall colour accuracy now with dE 1.0 average measured. This was a very well set up mode, and likely to be preferable to most users who don’t have the means to calibrate the screen themselves to bring that extra level of accuracy to your work. Just tweak the brightness control to your liking.

Calibration

Calibration and profiling can produce excellent results if you have a suitable calibration device and software. This was profiled to 2.2 gamma, 6500k colour temp and to the sRGB colour space. You can see the recommended OSD settings above, and then further corrections and mapping of the slightly wide native gamut back to strict sRGB are taken care of at the profile level. If you want you can also try our calibrated ICC profile out.

General Usage

The XG309CM offers a range of features showing that Asus’ focus is not just on gaming with this model. The inclusion of things like USB type-C with DP Alt mode and a 15W power delivery making single cable connectivity simple from supporting laptops for instance. We would have liked a higher power delivery here perhaps to keep up with other screens offering higher. There’s also a built in KVM switch which can be useful for multi system control from a single keyboard and mouse, a USB hub with 2 ports, basic integrated 2x 2W speakers and a headphone out connection. It would have been useful to have USB ports and the headphone connection on the side of the screen for easy access on this model, as the ports are very hard to reach and tucked away quite a lot at the back, making them a bit difficult to use. Obviously the speakers are very basic, but fine for the odd “office sound”, mp3 or YouTube video.

The IPS-type panel offers some solid all round performance including wide viewing angles and a stable image quality. This has made IPS very popular in the general-use space for a long time. The contrast ratio of this technology is not as good as VA panels, and in fact quite mediocre on this model even for an IPS panel at ~830:1. On dark content you get a familiar pale glow from an angle, especially noticeable in darker room conditions as well.

This is a flat format screen which is quite rare in today’s market of ultrawide curved which are usually curved to varying degrees. The size is ok for a flat screen we felt, it’s borderline whether a subtly curved format would have been slightly better, and we think any wider screen than this would be better for most users if it’s curved.

Text size is comfortable although on the larger size relative to other common screen sizes. There is a 2560 x 1080 resolution provided on a 29.5″ sized screen which gives you a pixel pitch of 0.270mm. This means text size is a fair bit bigger than say a 27″ 1440p screen (0.2335mm) and so you lose a bit of the sharpness and clarity that those higher density screens offer. The font size here is closer to a 24″ sized screen at 1080p (0.2767mm) so for those looking to upgrade from a screen in that size range, and who want a similar text size, this is a good option. For office work we found the 1080 pixel vertical resolution a bit restrictive and it limits your vertical space quite noticeably compared with a common 27″ 1440p model. The horizonal resolution of 2560 though provides a nice boost over 1920 screens and makes split screen multi-tasking much easier. This widescreen format is better for productivity and office use than a 1920 x 1080 screen, but not as good as a 2560 x 1440 screen. Probably obvious that it would sit somewhere in the middle there.

The screen has a blue peak at 456 nm, and although it is not part of the Eyesafe certified range of products, it does have a blue peak that is just beyond the supposed harmful range according to Eyesafe which is 415 – 455nm. There are also a range of blue light reduction modes in the OSD from levels 0 – 5 (0 being off). Each seems to make the image slightly more greenish in colour and makes the image slightly warmer as well, therefore reducing the blue peak a bit. Level 1 is about 5779k, while the max level 5 is 4784k.

Response Times and Gaming

The XG309CM is based on a so-called ‘Fast IPS’ panel from AU Optronics (M300DAN01.0) with a quoted 1ms G2G response time. There are 6 levels of overdrive available in the OSD menu to help you tweak and optimise performance, with the screen also being advertised as supporting variable overdrive which is rare on screens without NVIDIA’s Native G-sync chip.

There is a high 200Hz native panel refresh rate, with a further boost to 220Hz thanks to an overclocking feature that Asus have added. The screen supports adaptive-sync for variable refresh rates (VRR) from both AMD and NVIDIA systems with a range of 48 – 220Hz supported via DisplayPort, with LFC as well. The screen has been certified under the AMD ‘FreeSync Premium’ scheme, and Asus’ website says that certification under the NVIDIA ‘G-sync Compatible’ scheme is in progress as well, although that is not currently listed on NVIDIA’s site. We don’t really like manufacturers listing these specs as “pending” or “in progress”, as it could be misleading if this is never actually awarded. We’d rather manufacturers only list certifications that are already awarded.

The screen also supports Asus’ ‘ELMB-sync’ (Extreme Low Motion Blur Sync) technology which offers a strobing blur reduction backlight, that can be combined with VRR as well. Within the OSD menu are a range of ‘GamePlus’ gaming settings like a shadow boost, crosshair, timer, stopwatch, FPS counter and display alignment settings. These are also available quick launch via a menu accessed by the joystick controller. There’s a wide range of preset modes in the ‘GameVisual’ menu as well for different uses including Racing, RTS/RPG games, FPS mode, MOBA and a customisable User Mode. Certainly plenty of settings and options to play with to get the screen set up as you like.

A summary of the XG309CM gaming features and performance is included here for quick reference, but is discussed in a lot more detail below.

Response Times and Motion Clarity

We first tested the screen at the native 200Hz max refresh rate (we will test the overclocked mode in a moment) and in each of the overdrive modes from level 0 (off) to level 5 (max). A series of visual subjective tests and objective measurements with our oscilloscope were used to try and determine the optimal mode at this max refresh rate first of all. We have not bothered to included level 0 or level 1 here as they offered no visual benefit beyond level 2 which was the optimal setting we felt. At level 2 the response times were good (4.1ms G2G average), they could keep up very nicely even with the high refresh rate (90% refresh rate compliance), and there was also very low levels of overshoot – nothing visible in practice really. Motion clarity was very good thanks to the combination of good response times and a high refresh rate, and moving objects looked sharp and clear.

Moving up a step to the level 3 overdrive mode, which is actually the screen’s default setting, also looked pretty decent in practice but did start to show a slight pale halo behind moving objects like in the familiar Blurbusters UFO test. We didn’t think the small improvement in G2G figures to 3.7ms average was worth that. The higher modes like level 4 and level 5 just pushed things even further, driving the G2G figure a bit faster but at the cost of some higher overshoot and more pale artefacts. This never looked horrendous in real use, with fairly subtle pale halos being evident, but it was still distracting. The level 2 mode appeared to be optimal here.

Sticking with this optimal level 2 setting, we measured the response times then at a range of refresh rates to simulate performance during VRR situations, or if you are using other inputs like a games console or other external device. You can see that Asus have done a decent job of adding variable overdrive to this screen which is pleasing. This results in the response times getting slightly slower as the refresh rate lowers, which helps in turn to control the overshoot levels and means they never become problematic in level 2 mode. Overshoot creeps up a bit at the lower refresh rates but it’s still very subtle. This means there is thankfully a single overdrive mode experience on this screen, so you never have to worry about changing this setting during your gaming or other uses. Just stick with level 2 and you’ll be fine.

The overclocking mode seemed to work fine as well, with some improvements to response times thanks to the variable overdrive and ensuring the pixel transitions can keep up with the slight increase in the frame rate. We didn’t experience any issues with flickering or artefacts because of the overclock, so this seemed to be a viable mode to use if you want that extra 20Hz, and of course if you can power 220fps for your games.

We also captured some pursuit camera photos above at the max 220Hz overclocked refresh rate, and in the optimal Level 2 overdrive mode. These are designed to capture real-life perceived motion clarity and give you a good indication of how the screen looks in actual use.

For a fixed 60Hz input like an older games console or a Blu-ray player you could switch down to the level 0 (overdrive off) mode if you want to completely eliminate all overshoot, but it’s not really necessary. It maybe clears up the image a little so it’s an option if you need. We include the measurements here for completeness.

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Lag

We should note here as well that we measured a super low input lag on the XG309CM. There was a total display lag of only 1.90ms and with ~1.85ms of that accounted for by pixel response times, that leaves a signal processing lag of only ~0.05ms which is excellent. As a result the screen is perfectly fine for fast paced competitive games if you need.

HDR Gaming

We will reference “HDR” here briefly only because Asus choose to position this screen on their product page as a “29.5-inch 2560 x 1080 HDR gaming monitor” – the extent of the HDR capability here is limited purely to the screen accepting an HDR10 input signal and tone mapping the content to the appropriate gamma curve. There is a max brightness of ~350 nits from our testing so it can’t even reach the lowly HDR400 certification level, and is no better in HDR mode than it is in SDR. There is no backlight local dimming which would be necessary to actually improve the dynamic range / contrast ratio, so the screen cannot actually offer any contrast beyond the fairly mediocre ~830:1 native panel contrast sadly. The screen accepts a 10-bit input signal, but the panel itself is limited to 8-bit only with an additional FRC stage seemingly added by the scaler. So there’s minimal benefit there in terms of colour gradation. The display is also a standard gamut only model, so even lacks the colour enhancements associated with HDR which require a wider colour space. So all in all, despite the slightly dubious marketing, there is no real HDR capability here at all.

Console Gaming

The screen features the older generation HDMI 2.0 connectivity and capabilities with just a single port provided. Despite the screen having only a 2560 x 1080 panel resolution, the screen can accept inputs of higher resolutions, that it will scale down appropriately. You can input 3840 x 2160 “4K” at 60Hz, or 2560 x 1440 at 60Hz if you want and black borders will be added to the sides. Likely the most appropriate option though would be to input 1920 x 1080 resolution given 1080 is the native vertical number of pixels on this panel, and this should offer the sharpest image. There’s no real benefit in inputting higher here. This will also allow you to then push the screen up to 120Hz which it supports at this resolution even over HDMI 2.0. That will also allow you to prioritise refresh rate/frame rate in your games from the console, as there’s little point trying to drive a higher resolution when the screen won’t even support it.

We confirmed also that the screen supports FreeSync over HDMI, giving VRR support for Xbox that supports that, although it is questionable whether Sony will ever add this for the PS5. Because it’s the older generation HDMI 2.0 capabilities, there is no HDMI-VRR, which might have made VRR for PS5 in the future more likely, but doesn’t matter for Xbox at all. It will not support ALLM, Dolby Vision or 24Hz signals but can support 50Hz and HDR10 content.

ELMB-Sync Motion Blur Reduction

The XG309CM also includes Asus’ ELMB-sync (Extreme Low Motion Blur Sync) strobing blur reduction backlight mode. This can be used at the same time as variable refresh rates (hence the “sync” in the name) as well as at fixed refresh rates, although not at 60Hz for those who are interested in that. There are two ELMB modes available in the OSD menu called ‘Standard’ and ‘Turbo’. The turbo mode basically just changes the strobe length, making it a bit shorter to try and help improve the motion clarity a bit more, but at the cost of some screen brightness. We measured a brightness maximum of ~139 cd/m² in the ‘standard’ mode, but this drops down to ~103 cd/m² if you push in to the ‘turbo’ mode instead. Asus also provide an option called ‘clarity position’ which controls the strobe timing, allowing you to tweak which part of the screen offers the cleanest image.

We took some pursuit camera photos of the top, middle and bottom regions of the screen with ELMB-sync set to ‘turbo’ and with clarity position focused on improving the image in the middle part of the screen. You can see there is some moderate ghosting to the image in places due to the strobe cross talk, which is hard to eliminate on any LCD display. The image did look sharper and cleaner, and was easier to track across the screen thanks to this blur reduction mode but rather than getting blur to the moving image, you get some ghost trials. The screen can’t get particularly bright sadly, even in the ‘standard’ mode which may be a little limiting to some users. The ability to combine this mode with VRR was a big plus point though.

Conclusion

The XG309CM was an interesting new option to test with an uncommon size, resolution and format combination in the gaming monitor space. It offers a mid-ground for those wanting an ultra-wide format and aspect ratio, but who perhaps don’t have the space for the more common 34″+ sized displays that are readily available. Whether or not the flat format is better than curved for a screen like this is probably down to taste, but we felt it was fine given the more modest size. By dropping to a modest 2560 x 1080 resolution, which is adequate on a screen this size but that is too low for larger screen sizes really, it gives you room to focus on driving refresh rate higher than those larger models instead. The availability of a very high refresh rate of 220Hz is great here, and makes it suitable for fast faced gaming for sure.

Looking at the gaming experience we were impressed by the very good response times, the extra implementation of variable overdrive and the low levels of overshoot in the recommended level 2 mode. Motion clarity was very good, and there were no annoying artefacts to note. The high refresh rate really helped here too, providing a decent bump above common 120 – 144Hz screens in the gaming space. With the resolution being on the lower side, hopefully this is easier to achieve for more people too. Input lag was super low, there were the usual good range of Asus gaming extras and settings, and for those who like blur reduction modes, the ELMB-sync mode worked pretty well too. As ever, the support for adaptive sync for VRR was very useful. One area of gaming the screen doesn’t do well at is HDR. There’s no real HDR capabilities here at all, so don’t expect to use this display for that kind of use, either for HDR gaming or videos.

Away from gaming Asus have done a nice job providing some additional features and capabilities. The USB type-C connection, KVM switch and even the camera mount might well be useful for general work and productivity enhancement. The resolution is a bit limiting for office work compared with the wide range of 1440p screens, or ultrawides with a higher 3440 x 1440 resolution because of the reduced vertical space here. But it is better than a normal 1920 x 1080 screen for multi-tasking, so sits somewhere in the middle. Fine for many people we are sure, but we do miss the extra space of larger screens.

The XG309CM is a standard gamut model only, which is quite rare actually in today’s market. This does mean that default setup, and especially the factory calibrated sRGB mode, are more accurate and usable for normal SDR work and typical content. That makes it easier and more accessible for these applications than common wide gamut screens. On the other hand you may miss the vividness and saturation of a wide gamut model for gaming and multimedia. The default setup was good, but the one problem was the mediocre contrast ratio which was a shame. Otherwise the IPS panel performed very well as expected.

If you’re interested in moving to an ultrawide format but want something that isn’t too large, this is worth a look. You’ll get higher refresh rates than many other ultrawides too, some very good gaming performance and a decent range of functions and features. You can check availability and latest pricing from our links below.

	Check pricing and availability in your region

• Further reading – if you’re after a different gaming screen you should also check out our TFTCentral Recommendations List for Gaming Monitors

Pros	Cons
Very good response times and high 220Hz refresh rate	Mediocre contrast ratio
Nice additional features like USB-C, KVM and camera mount	Resolution a bit limited compared with larger ultrawides
Very accurate and usable factory calibrated mode	No HDR capabilities, despite the marketing

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