Asus XG27AQDMG Discussion

[kurtdh]

Here, it just works. Sorry. Don't know why it doesn't work for you :-/

Oh, also CRU doesn't work if DSC is active, which explains why I can't tweak this monitor even with DisplayPort.

[kurtdh]

Here, it just works. Sorry. Don't know why it doesn't work for you :-/

I'm thinking of returning this monitor due to these issues and getting the XG27AQDMG instead. Just to confirm, you own this monitor and you fixed flicker completely just by reducing the vertical total correct? What does lowering that number affect exactly?

[RealNC]

I'm thinking of returning this monitor due to these issues and getting the XG27AQDMG instead. Just to confirm, you own this monitor and you fixed flicker completely just by reducing the vertical total correct? What does lowering that number affect exactly?

With modern displays, this is used to control how fast each frame should be scanned out. Lowering this reduces the scanout speed.

However, I've been testing this a lot in different FPS caps, and apparently it affects g-sync in a negative way. G-sync seems to work, with all the side-effects of it (monitor OSD Hz indicator is fluctuating, the mouse cursor will update at the same FPS as the game instead of being fixed to 240Hz as with g-sync off,) but I can see some frame skips sometimes, especially at lower FPS. It's not flawless.

Also note that when disabling DSC in the XG27AQDMG OSD, 240Hz gets limited to 8-bit (normally it's 10-bit, and the panel itself is native 10-bit.) So if you want HDR at 240Hz, you will need to enable DSC, otherwise you're getting 8-bit HDR.

[kurtdh]

I'm thinking of returning this monitor due to these issues and getting the XG27AQDMG instead. Just to confirm, you own this monitor and you fixed flicker completely just by reducing the vertical total correct? What does lowering that number affect exactly?

With modern displays, this is used to control how fast each frame should be scanned out. Lowering this reduces the scanout speed.

However, I've been testing this a lot in different FPS caps, and apparently it affects g-sync in a negative way. G-sync seems to work, with all the side-effects of it (monitor OSD Hz indicator is fluctuating, the mouse cursor will update at the same FPS as the game instead of being fixed to 240Hz as with g-sync off,) but I can see some frame skips sometimes, especially at lower FPS. It's not flawless.

Also note that when disabling DSC in the XG27AQDMG OSD, 240Hz gets limited to 8-bit (normally it's 10-bit, and the panel itself is native 10-bit.) So if you want HDR at 240Hz, you will need to enable DSC, otherwise you're getting 8-bit HDR.

Thank you for this. Yes, I did use the Linus tech tips DSC calculator and figured out I would be stuck with 8-bit instead of 10-bit. I'm kind of on the fence now as to whether to keep my 4K 240HZ FO32U2P. VRR flicker hasn't been a major issue for me in regular gameplay, but is present in lots of menus in the games I play and is annoying. I'm afraid I'll end up playing a game in the future where it flickers all the time during normal gameplay. I love the additional detail of 4k over 1440p as well. There's also the prospect of nvidia fixing their drivers to allow EDID overrides with DSC enabled, and there's also the option of me not using DSC in the future with a 5 series nvidia card that hopefully supports DP 2.1. This means I would be able to use CRU and potentially mitigate/fix VRR flicker in the future, which gives me hope!

Obviously disabling VRR fixes all the flicker issues. Which brings me to an important question. When I turn off VRR, I haven't noticed any screen tearing. My game usually runs around 80-130 FPS. Is there any point to using VRR at all if I don't notice screen tearing? Does it provide any other benefits like smoother gameplay or anything that I could potentially benefit from? I can't tell the difference between VRR off and on, at least when playing New World.

[RealNC]

There's also the prospect of nvidia fixing their drivers to allow EDID overrides with DSC enabled

I just tested DSC here and the override works just fine at 1440p 240Hz 10-bit. DSR and DLDSR also work fine with DSC, btw. This is on Windows 10.

Obviously disabling VRR fixes all the flicker issues. Which brings me to an important question. When I turn off VRR, I haven't noticed any screen tearing. My game usually runs around 80-130 FPS. Is there any point to using VRR at all if I don't notice screen tearing? Does it provide any other benefits like smoother gameplay or anything that I could potentially benefit from? I can't tell the difference between VRR off and on, at least when playing New World.

VRR fixes animation judder when FPS does not match Hz. But what I'm seeing with this flicker fix is that there's still some judder. G-sync has trouble syncing correctly with this tweak.

So I'd say keep your monitor. If you don't notice issues without VRR, and vsync + frame cap doesn't give you stutter, I'd say keep your monitor.

[kurtdh]

I just tested DSC here and the override works just fine at 1440p 240Hz 10-bit. DSR and DLDSR also work fine with DSC, btw. This is on Windows 10.

With Displayport 1.4 or HDMI 2.1?

[RealNC]

With Displayport 1.4 or HDMI 2.1?

DP 1.4.

[kurtdh]

With Displayport 1.4 or HDMI 2.1?

DP 1.4.

Interesting, the dev said DSC shouldn't work with CRU, but maybe it does with some CRU tweaks but not with others. You using YCbCr 4:2:2, but not 4:4:4 maybe? I'll ask him.

[RealNC]

Interesting, the dev said DSC shouldn't work with CRU, but maybe it does with some CRU tweaks but not with others.

DSC is weird with Nvidia. For example DSR/DLDSR + DSC doesn't work with some displays, but it works in others. Maybe it's related.

You using YCbCr 4:2:2, but not 4:4:4 maybe? I'll ask him.

Neither. It's set to "RGB".

[kurtdh]

Interesting, the dev said DSC shouldn't work with CRU, but maybe it does with some CRU tweaks but not with others.

DSC is weird with Nvidia. For example DSR/DLDSR + DSC doesn't work with some displays, but it works in others. Maybe it's related.

You using YCbCr 4:2:2, but not 4:4:4 maybe? I'll ask him.

Neither. It's set to "RGB".

This is what the CRU dev said, fyi:

"I looked more into it and NVIDIA says this: "NVIDIA DSR, NVIDIA DLDSR and NVIDIA Image Scaling are supported when DSC mode is enabled, if the pixel rate needed to drive the display mode does not exceed the GPU's single head limit. If GPU uses two or more internal heads to drive the display, NVIDIA DSR, NVIDIA DLDSR and NVIDIA Image Scaling are not supported."

That doesn't explain why they need to disable EDID overrides, but it seems tied to this. They don't say what the single head limit is, so I don't know the exact logic that NVIDIA is using to disable EDID overrides and DSR/DLDSR. All I know is everyone with this problem has a monitor with DSC, but apparently it has more to do with the bandwidth required for the highest resolution and refresh rate. Regardless of the cause, the limitation is definitely on NVIDIA's end and not the monitor or CRU."