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Flicker issues with KDE Wayland at frame rates >100 fps

Hello Everyone,

Regarding this flicker issue, I’ve reached out on Reddit (got just advertisement bots) and discuss.kde.org (got recommended here) about this issue, but have not gotten much in the way of a resolution to my current problem. Both topics are here if it matters... https://www.reddit.com/r/kde/comments/17dhwo2/flicker_issues_with_kde_at_frame_rates_100_fps/?sort=new https://discuss.kde.org/t/flicker-issues-with-kde-at-frame-rates-100-fps/6411

Anyway, I’ve recently upgraded my PC setup so that I could achieve a display of 4k 144hz. The main parts of my setup consist of an Eve Spectrum 4k 144 Hz Monitor 27” (Glossy) monitor, a AMD Ryzen 7 7800X3D CPU, a Sapphire NITRO+ Radeon RX 7900 XTX 24 GB Video Card, and 32 GB of ram. I’m using Display Stream Compression as well (DSC: 1.4) with the monitor in order to make 4k 144hz possible. Without it, 4k 120hz seems the maximum possible.

I’m currently using KDE Wayland (using Nobara or Kubuntu as the distro) to take advantage of Adaptive Sync which Gnome KDE still seems to struggle with. Also just generally prefer KDE to Gnome in general. I also have Windows installed on a separate hard drive for doing things I can’t figure out in Linux in the rare circumstance Wine or an equivalent doesn’t work for me or if I just want to check something.

Using the KDE Wayland setup, I have no issues as long as I don’t go above 100 fps. However, if I try to increase my FPS beyond this to 144 Hz or even 120 Hz, I start getting intermitant “flickering”. This is peculiar in that if I setup Windows to run at 4k 144 Hz, there is no issue whatsoever, with no flickering occurring.

I’ve tried a few things to resolve this issue, none of which have worked. Specifically…

  1. I tried 2 different DisplayPort cables in case that was the issue. Specifically, I’ve tried these 2 cables listed below (which both claim to do 4k 144 Hz), but this has not solved the problem. Either way, as 4k 144 Hz runs fine on Windows with either cable, I doubt this is a cable issue.

  1. At one point I thought that a lower Color Bit Depth may allow me to have non-flickering higher frame rates. This may still be true, although Windows with DSC is still able to achieve 4k 144 Hz with a color bit depth of 10, so I’m not sure. Anyway, Windows via Radeon Crimson Edition (and maybe some other way) can flip this from 10 to 8 (or 30 to 24 if counting all colors). KDE Linux doesn’t let this be changed as easily, although (apparently…?) it can be changed by adding the line KWIN_DRM_PREFER_COLOR_DEPTH=24 into /etc/environment according to the below topic I made some months ago dealing with a somewhat similar issue. Not sure if I need to run something else to update this though (similar to how updating grub requires a few commands). What I have done has not gotten rid of the flickering though. The topic is here by the way… https://discuss.kde.org/t/kde-wayland-view-set-color-bit-depth/2019

  2. I also tested whether Display Stream Compression is working. My monitor has 3 settings for DisplayPort mode, being 1.2, 1.4 without DSC, and 1.4. Using 1.4 without DSC has 4k 120 Hz show up in my options menu (although 144 Hz isn’t there), but trying to select it still results in flickering at best or a black screen at worst on some distros, that only goes away once the system resets to a previous fps. Using 1.4 instead does let me go to 144 Hz and I can actually get the display to work…although with flickering. So, DSC seems to be doing something at least. Not sure how to test if it is working properly, although as I believe 4k 120 Hz is the cap with 1.4 with DSC, the fact it is working on Windows also makes it seem like it isn't the culprit.

  3. I've also tried distro hopping to get rid of the issue. I've tried Nobara, Fedora, and Kubuntu (also tried to get MX Linux with KDE working, but the flickering issues were even worse). They pretty much all have the same problem. Maybe it is my imagination, but maybe Kubuntu does it slightly less? All the same, flickering is still common enough at high frame rates that it isn't a usable solution.

In summary, with Windows running 4k 144 Hz without issue, the monitor appears to have the ability to run this resolution/frame rate. I’ve also tried 2 DP cables in case 1 had an issue with Linux for some reason, messed with changing the color depth, looked into where DSC was working correctly, and also did a bit of Distro hopping.

I can't seem to figure out what is causing the issue, although it appears to be Linux specific. Zamundaaa, who is a KDE Developer, said that it sounds like my connection isn't very stable, and if the hardware works, then it's most likely a driver bug. He/she said to ask here for more qualified help.

So, is anyone able to assist? If it helps, I have my system settings listed when I'm using KDE Wayland via Kubuntu in the inserted imageImage