'

Nvidia's G-Sync HDR 4K 144Hz monitors reportedly use Blurry Chroma Subsampling at over 120Hz

The display's 'Overclocked' mode is said to look noticeably worse

Nvidia's G-Sync HDR 4K 144Hz monitors reportedly use Blurry Chroma Subsamping at over 120Hz

Nvidia's G-Sync HDR 4K 144Hz monitors reportedly use Blurry Chroma Subsampling at over 120Hz

Nvidia's G-Sync HDR monitors have started to release at retailers in limited quantities, offering 27-inch 4K HDR10 compliant panels that can provide a refresh rate of up to 144Hz with G-Sync adaptive framerate technology.  

Early reports from users seem to indicate that these displays offer noticeably worse image quality when running in their 144Hz "overclocked mode" instead of its standard 120Hz configuration. These early reviews have brought forth reports that this lack of visual parity is "due to the 4:2:2 chroma subsampling",  though it is worth noting that this conclusion comes from Reddit user Glennwing, who doesn't own an Acer X27 or ASUS ROG Swift PC27UQ G-Sync HDR display.  

We have asked ASUS for clarification regarding the ROG Swift PC27UQ's overclocked 144Hz mode, though reports of it using 4:2:2 chroma sub-sampling would easily account for the visual differences that some end users have reported. 4:2:2 pixel subsampling retains the pixel brightness information of the image while removing half of the colour information, which at 4K creates a colour resolution of 1920x2160, blurring the final image. This effect is especially noticeable when reading text. 

Today's DisplayPort 1.2 monitors are limited to a refresh rate of 60Hz at 4K resolutions, as bandwidth is not available to transfer higher resolution images to a display. This limitation is why Nvidia's new G-Sync HDR monitors make use more modern iterations of the DisplayPort standard, with version 1.3 offering a 2x boost in raw bandwidth while 1.4 gives users VESA Display Stream Compression (DSC) technology. DSC can provide users with up to a 3:1 compression ratio that is "virtually lossless", facilitating higher resolutions and framerates. DSC requires time to decompress the visual signal on the display side, adding a small amount of lag to monitors using DSC. 

If we assume that Nvidia's G-Sync HDR monitors, Acer's X27 or ASUS' ROG Swift PC27UQ, don't use VESA's DSC compression technology, we can also assume that the framerate limit of the display is 120Hz with full chroma sampling (4:4:4), presenting issues when display makers increase refresh rates further. This is why many expect Nvidia's G-Sync HDR displays use Chroma Subsampling to achieve 144Hz refresh rates.  


Nvidia's G-Sync HDR 4K 144Hz monitors reportedly use Blurry Chroma Subsamping at over 120Hz

 

Both Acer's X27 or ASUS' ROG Swift PC27UQ say that they offer an "overclocked" 144Hz mode to their users and a 120Hz refresh rate in standard mode, with both display manufacturers failing to specify whether or not their ultra-high-end $2000 4K G-Sync HDR displays use Chroma Subsampling to achieve 144Hz refresh rates.

It is possible that Nvidia's G-Sync HDR modules do not support DSC compression technology, or that Nvidia has decided not to use it to minimise latency.  This issue is perhaps why Nvidia's Big Format Gaming Displays (BGFDs) are all max out at 120Hz, removing the rumoured 144Hz sub-sampling issue entirely.    

This controversy leaves us in a situation where two of the most expensive displays on the market may not offer what they advertise, as their 144Hz mode isn't exactly what most monitor buyers consider an "overclock".

We have reached out to ASUS for a clarification regarding the specifications of their ROG Swift PG27UQ G-Sync HDR monitor, though it looks like the monitor's 120Hz mode will be preferable if users prefer pixel perfect image accuracy.

You can join the discussion on Nvidia's G-Sync HDR 4K 144Hz monitors reportedly using Blurry Chroma Subsampling at over 120Hz on the OC3D Forums

«Prev 1 Next»

Most Recent Comments

18-06-2018, 17:05:00

AngryGoldfish
Premium price for a premium product...Quote

18-06-2018, 17:44:26

tolagarf
Quote:
Originally Posted by AngryGoldfish View Post
Premium price for a premium product...
Which gives you a premium piece of junk. I still can't stop scratching my head about that fan located in the back of the Acer monitor. Someone thought that was an awesome idea apparently...Quote

19-06-2018, 01:08:02

Peace
Quote:
Originally Posted by tolagarf View Post
Which gives you a premium piece of junk. I still can't stop scratching my head about that fan located in the back of the Acer monitor. Someone thought that was an awesome idea apparently...
4k144 is completely useless anyways, so it was alrready designed as a piece of junk.

So we should avoid these monitors. But should we avoid DP 1.4 in general, because of DSC and its lag?Quote

19-06-2018, 02:15:30

tolagarf
Quote:
Originally Posted by Peace Ð View Post
4k144 is completely useless anyways, so it was alrready designed as a piece of junk.

So we should avoid these monitors. But should we avoid DP 1.4 in general, because of DSC and its lag?
Oh? I haven't even read anything about that. What's that all about?Quote

19-06-2018, 08:41:20

Giggyolly
I've been saying this since the monitors were announce.. DP 1.4 can only handle 120Hz at UHD, so ery is needed to go above 120Hz.

Why th eneed to go striaght for 144Hz, 120 would be awesome as a fist release, probably easier for them too!Quote
Reply
x

Register for the OC3D Newsletter

Subscribing to the OC3D newsletter will keep you up-to-date on the latest technology reviews, competitions and goings-on at Overclock3D. We won't share your email address with ANYONE, and we will only email you with updates on site news, reviews, and competitions and you can unsubscribe easily at any time.

Simply enter your name and email address into the box below and be sure to click on the links in the confirmation emails that will arrive in your e-mail shortly after to complete the registration.

If you run into any problems, just drop us a message on the forums.