£600 4K 144Hz Nano IPS Gaming Monitor – X= XRGB27UHD Review

Back when I reviewed the Asus PG27UQ at the start of 2019 I was blown away, both by the experience, and the price tag. Dropping two grand on a monitor – one that even a 2080 Ti struggled to supply enough frames to actually enjoy – seemed a bit mad. But now there are new GPUs, sure you can’t get any, but they do exist! And the monitors have dropped in price, by a whole lot! People like LG are selling their 27GN950-B for between £800 and £1000, which is still a whole lot but it’s literally half the price of that OG option. But what if I told you that you could get the exact same panel for just £600 instead?

Enter the XRGB27UHD. This uses the same LG LM270WR8-SSA1 panel as the 27GN950-B, the same 3840×2160 144Hz Nano IPS panel with a quoted 5ms GtG response time, 450 nits of peak SDR brightness or 600 nits in HDR, 1000:1 contrast ratio, and 99% coverage of the DCI-P3 spectrum. Damn, that’s fancy.

Now, those cost savings have to come from somewhere. That starts with the stand. It’s… fine… but only features tilt adjustment, not height, swivel or rotation. Now, it does have a VESA mount so that’s not the absolute end of the word, but since most people still use the included stand it’s worth noting. On top of that, even trying to install the display on it’s stand is a pain, as you really need to slam it in place to get it to lock. Like, worryingly hard.

The rest of the build quality is the same, it’s fine, no major complaints, but it’s a far cry from premium. You do get some RGB lighting on the back – it’s much more tasteful than the logo projector from their 1440p model that shares the same stand and body, but it’s still not the utmost premium. Hell, even the joystick dial to control the very basic on screen menu is rather loose and cheap feeling plastic.

Speaking of the menu, you’ve only got a handful of options you’ll be interested in, namely under “Picture Quality Setting”, “Response Time”, aka overdrive. That has four options, off, high, middle and low – which as you’ll see in a moment, low is the only one I’d recommend here. Then down in the “Other” section you’ll find the options for Adaptive Sync which appears to be disabled by default, alongside the “MPRT” setting, aka backlight strobing, and the same confusing “Flicker Free” setting which as I explained in my last X= monitor review is nonsensical at best.

I mentioned the MPRT setting, or backlight strobing among friends, which on most monitors means the backlight turns off for all but 1ms per frame, to achieve the usual quoted “1ms MPRT” figure. This monitor in particular actually quotes a 0.8ms MPRT time, which is hilarious because as far as I can tell it’s false in two separate ways. First is timing. This footage was recorded at 1000FPS, meaning each new frame is being captured 1ms apart. The shutter speed is also set to 1/10000 s, so it captures 0.1ms worth of light, then waits 0.9ms before capturing another one. Let’s count how many frames the image is being fully displayed, 1.. 2… and a half? Let’s be kind and say 2ms. So, it’s 2ms, not 0.8ms.

The second, and honestly funnier problem is that it doesn’t actually clip to black. The image is still fully there, just only in red. Now I’m not sure if this is something that you would experience with the LG monitor as they don’t implement that option, but it certainly looks like they are turning off the blue and green sub pixels but forgot to do the same for the red sub pixels. That means the image is still being displayed, which means the MPRT could be considered the full refresh rate time of 6.9ms. On top of that, while many backlight strobing modes often give me pretty bad headaches pretty quickly, something about this whole ‘drop to red’ thing, the instant I turned the setting on I got a blinding headache and had to look away, only looking through mostly covered eyes to immediately disable it. That’s not great.

Now, something your extra cash on the name-brand model buys you is development time on the overdrive modes. According to RTINGS review of the 27GN950, all but the maximum overdrive setting provides a steady decrease of the response time, generally without the side effect of bad overshoot. Sadly on the XRGB27UHD, all but the ‘Low’ setting have increased perceived response time and pretty horrific overshoot – as much as 95 RGB values higher than the target, or 62%! Even the “Middle” setting is pretty lackluster, with an unpleasant amount of overshoot present and still relatively long response times to boot. Only the “Low” setting offers a worthwhile performance boost without affecting the overshoot figures significantly. This is the exact sort of thing that the R&D teams will spend their time tweaking to get just right, but that doesn’t seem to have been done here.

That overshoot isn’t just on-paper either, the UFO test shows just how bad it looks. Even while gaming it’s very, very noticeable and pretty off putting. On the “Low” setting I’d actually recommend, the UFO does get fully drawn before the next frame starts, but only just which fits with the 6.3ms average response time I recorded with OSRTT. With overdrive off you have a slightly slower response, more like 8ms on average, which is displayed in the UFO test as well where it can’t fully draw the UFO in time, nor can it clear the old frame in good time meaning you have ghosted frames on screen. Still, it’s far from the worst panel I’ve seen for sure!

When it comes to input lag, my time sleuth reports this at 5ms which isn’t great. Most other monitors I test, even 4K panels, run more like 1ms so this isn’t ideal. The only catch is the time sleuth caps at outputting a 1080p60 signal, whereas the scaler in the display is going to be outputting a 4K144 signal to the panel meaning the scaler will have to do some translation. Like I said though, some other 4K panels I’ve tested don’t have that problem so take that with a pinch of salt. I also test the total system or click to photon input lag which is a much more respectable 22ms – that’s from clicking the mouse to seeing a flash on screen from CSGO.

Actually gaming on this isn’t exactly bad, I mean it’s still a rather nice 4K 144Hz panel with in the grand scheme of things pretty decent response times and input lag. Being a 27 inch 4K panel, the pixel density is insane making this very, very crisp. It’s plenty fluid and smooth, and rather vibrant too, although I wouldn’t go so far as to say it’s a perfect experience especially for fast paced games. I’d see it as a pretty good all-rounder though, I think most genres would play well here.

I mentioned vibrance – that comes from the fact this is a Nano IPS panel meaning it has nanoparticles on top of the LED backlight which absorb excess wavelengths of light meaning essentially ‘cleaner’ light goes into the sub pixels allowing for a more accurate and wider colour gamut. Specifically, quoted 99% coverage of the DCI-P3 spectrum. My SpyderX reads is at more like 97% coverage, although the SpyderX is only rated for 100% DCI-P3 coverage itself which can make that sort of tolerance a little inaccurate and from just looking at it I’d be happy to agree with the spec sheet. This looks great, and actually if you drop it to run at 120Hz (if you are using DisplayPort anyway) you can get 10 bit colour too.

As for brightness, to the eye it’s perfectly fine. 100% is too bright for me to comfortably use, which is exactly what you want. It’s quoted as offering 450 nits of peak brightness, but the best I could get was more like 350 nits. While that isn’t a massive deal for real world usage, it does put a further nail in the HDR coffin as I got less brightness in HDR mode (both on the monitor and in Windows), and frankly it looked awful. It’s not something I’d even consider enabling personally. That also means the contrast ratio is a little lackluster, I measured it at 873:1, again a little short of the 1000:1 quoted.

For content consumption though it’s a pretty nice experience. It’s certainly a nice sight, bright enough in SDR and again that 27” 4K pixel density makes it look incredibly sharp. Even if content creation is more your bag I could see this being a decent choice especially if you say edit 4K videos by day and game by night.

Audio wise, this does have some included speakers, but they are pretty naff so unless you absolutely have to I’d steer clear personally. There is one other sound source though, and that would be this…

Yes, that’s an active cooling fan. It runs whenever the display is on. It’s not all that loud, but as soon as my ears picked it up especially in a quieter environment I couldn’t not notice it. The majority of people who would use this sort of display won’t have issue with that, but if you are more sensitive to constant noise like this then you might want to steer clear.

So, compared to the more expensive LG 27GN950 (which is being replaced by the 27GP950 now), this is I think a less refined version. The overdrive is generic, the brightness doesn’t seem to match what the same panel offers on the LG version, and the physical build is definitely more budget, but I’d expect the actual experience of using it to be relatively similar. It’s still a very nice panel which can offer a visually stunning experience – gaming or not. So just buy one of these then? Well, there is one final to mention, which is the AOC U28G2XU.

That is also a 4K 144Hz IPS monitor with around the same actual brightness, albeit with a slightly smaller colour gamut at around 88% coverage of the DCI-P3 spectrum, a faster response time, a nicer adjustable stand, a proper OSD and controls, and the real catch is that it’s £569 on Amazon right now (affiliate link in the description). The only thing that might draw you to this X= instead is its HDMI 2.1 port, meaning it does support 4K144 over HDMI. Strangely though, the spec sheet lists this as having 1 2.1 port and 1 2.0 port, alongside it’s DisplayPort 1.4 port and USB 3 hub (and USB C for display in and using it as a KVM), but in my testing both ports happily ran 4K144 from my RX 6900 XT, but wouldn’t run 10 bit colour meaning it’s not the top end version of HDMI 2.1. Strange that both ran at 2.1 speeds though… Anyway, that’s a benefit for any console owners who would want to game at 4K120 (in theory anyway), so that may sway you towards this instead.

On the whole this certainly isn’t bad. It definitely lacks refinement especially in its firmware, and its build quality, but it’s hard to argue with such a stunning panel for 25% less than what LG would sell it to you for. Personally if I wanted a 27 or 28” 4K 144Hz IPS monitor, I’d probably go with the AOC U28G2XU instead – especially with its lower price tag – although if this were more like £550 and especially if it received some development time on things like the overdrive modes I could see myself swaying more towards this, and for sure the inclusion of HDMI 2.1 is a great benefit.