Choppiness with looking-glass-client

Hello, as my title states: I have a little problem with the looking-glass-client on my Linux system.

First of all here are my specs:

Arch Linux
Linux 6.0.7
KDE Plasma 5.26.2 X11
AMD Ryzen 7 5800X @ 3.80GHz
32GB DDR4 Ram Speed: 3200 MT/s
Radeon RX 6600 (Linux GPU)
Radeon RX 590 (Windows VM GPU via vfio)
AsRock Taichi X570

lspci output for RX 6600 in short: LnkSta: Speed 16GT/s, Width x16

lspci output for RX 590 in short: LnkSta: Speed 8GT/s, Width x8 (downgraded)

(I am fairly new to vfio stuff, I got myself the X570 board because of pci-e version 4 and therefore better performance in dual gpu setups instead of pci-e 3.0)

Windows 10 VM XML

My looking-glass-client terminal log (started with -F for fullscreen, no config)

Now to my problem.
The image appears to be choppy and not really 60fps sometimes and the transition feels not as smooth as when I use the Windows 10 VM directly via HDMI on my monitor.
This issue is hard to explain, so I made two very bad videos trying to show what I mean (Sorry for the phone video, but my phone has the ability to record in slow motion and this shows it a little better in my opinion)

I hope someone can understand what I am trying to say here or what my problem is, I really like looking glass and would like to sort this out somehow to get the best possible experience, maybe it already is the best possible experience, I don’t know, please take a look at the videos.

Sorry for my bad recording skills, I am not a director, I am just a Linux user :smiley:

Note: Both Linux and Windows run at 60Hz refresh rate, there is no vrr, also the game runs at 60fps and vsync on

With looking-glass-client

Direct hdmi output

I tried to disable kwin on Linux but it didn’t change the problem.

Thanks for your time and efforts

Why are you giving windows a slow GPU? The guest is working very hard to render and capture for transfer, I am not at all surprised that you’re having issues.

This is also not helping matters.

The RX590 does not support PCIe4

Wait a sec, I just looked through the VM xml and I recognise it, I have already discussed this with you in the LG discord. Closing this post off as we already have a running support discussion there.