Vertical lines on FreeSync 144Hz Monitor on AMD & NVidia

Hi guys,
As i want to ditch Windows, i made the transition with to Linux Mint. It is a pain to learn, but i understand that one can get used to it, so I stick with it :slight_smile:
The most pressing problem right now is actually my monitor. I have a 3x monitor setup:
Acer_G277HU + Acer_XG270HU + Acer_G277HU.
Basically 3x 1440p with the center one supporting 144Hz & FreeSync.

Now this FreeSync monitor is not working quite right.Acer_xg270hu|720x540
[I am new, i hope you can see the picture in full resolution]
Those vertical lines on the screen are there constantly there:

  • with my 5700XT using amdgpu driver (didnt get the pro package to work)
  • also with my GTX1080 using nvidia drivers
  • independent of the cable connection (DP1.2, DP1.1, HDMI)
  • independent of resolution and refresh-rate (via xrandr)
  • when i boot Fedora 31

The lines disappear if:

  • i have no driver installed (using kernel, works on every resolution
  • connect a Windows-PC
  • i take a screenshot and view it on a different monitor.

The vertical lines on the monitor seem to respond to what is displayed horizontally next to it. I have shown a light gray background, for clarity, but it is also there when i display a green image (then the lines are mainly green) or play a video.

Can anyone instruct me how to debug this issue and eventually solve it?

  • it is not an issue with signal integrity: the fact that it is cable and port and transport protocol independent tells me it is not.
  • it is not a broken monitor, because in Windows it works.
  • it is not a bad graphics card, because it happens on NVidia too.
  • It is not a rendering issue, since the screenshots are clear of any unwanted lines.