I recently switched from a 3440x1440 34 inches display (LG 34GN850P-B) to a 3840x1600 38 inches one (LG 38WN95CP).
The previous screen supported 144Hz refresh rate without any problem when connected to the KVM. The new one not so much apparently.
Up to 75 Hz, the display on the 38WN95CP is flicker-free. At 120Hz or 144Hz, it starts flickering with banding artefacts.
When the screen is directly connected to the GPU, I get a flicker-free display up to and including 144Hz. The issue starts when adding the 8KSW21DP-DM KVM to the loop.
I replaced all the cables with DP 2.1 8K@120 Hz certified ones.
When directly connecting the GPU to the screen, the cable works just fine at displaying 3840x1600@144Hz. All connections to the KVM are using the same cable types and brand (DP 2.1 8K@120 Hz certified).
I checked the KVM firmware version and it’s on the latest 1.0.2.
As the resolution 3840x1600 is just below 4K (3840x2160), I assume it should be supported up to 165Hz as well.
Could you please fix the display issue when using 3840x1600 resolution with a new firmware update?
Truly sorry I forgot to reply you that we have tested with LG monitor with same 3840x1600 resolution but cannot reproduced the high refresh rate issue in our lab, so need try to get other monitor to have a test.
Could you share a bit more on how you tested ?
Monitor model ? Was it the only monitor connected to the KVM ? etc…
In order to provide a bit more details on my setup, here are the monitors connected to the KVM:
as output 1, it’s the LG 38WN95CP
as output 2, I am using my former monitor, LG 34GN850P-B.
In order to drive both screens though the KVM, I am using an nVidia RTX 4080 super, connected on a pcie 16x slot.
The glitches have only appeared on monitor 1 since I upgraded to the 38WN95CP. They show up in the EFI menus too. The issue does not seem to be OS or driver dependent as far as I can tell.
I was successfully using dual 38WN95CP at their max refresh rate before that with the very same setup.
Thanks for your update, we only testing with the LG monitor: LG UltraWide 49WQ95C-W with 3840x1600.
So what is the monitor2 output resolution and refresh rate?
So we can try get a same or similar monitor(2) to have a test again.
Monitor 2 output is at 3440x1440.
It supports 60Hz, 100Hz and 144Hz.
The refresh rate has no influence on the occurrence of glitches on monitor1.
It can be any refresh rate on monitor2, as soon as I increase the refresh rate above 75Hz on monitor1 it starts to display glitches (on monitor1 alone). Monitor1 supports 60, 75, 120 and 144Hz.
120 and 144 Hz on monitor 1 definitely are producing the problem.