Arch Linux

thom.cherryhomes

Member

Registered: 2025-06-28

Posts: 1

Framerate cuts in half on Wayland when I attach external displays.

Hi.

I have:

a Thinkpad P17 Gen1 with a 4K eDP panel.
It is a Prime GPU setup with a NVIDIA mobile-RTX3000, and P630 Intel GPU
two LG 27 inch 4K displays, one hooked up via USB-C, another by DP, via Thunderbolt docking station.

monitors.conf has every display set to the same resolution and refresh rate (60Hz)

Any attempt at connecting an external display results in framerate being cut in half. glxgears shows an average of 26fps when connected to 1 or 2 external displays, with or without the internal eDP enabled.

Lowering the resolution on any/all displays does not fix it.
Changing the bus topology of the connecting displays does not fix it.
Telling prime-run to use the NVIDIA GPU does not fix it.

Does anyone know the fundamental nature of the problem? because every forum post I've seen is the equivalent of poking it with a stick until it works.

-Thom

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 73,732

Re: Framerate cuts in half on Wayland when I attach external displays.

Probably https://wiki.archlinux.org/title/PRIME# … ronization - both outputs are attached to different GPUs?
No idea how to impact that on wayland™, though - notably since wayland™ isn't a thing: which compositor is this specifically (gnome, kde, sway, hyprland, weston, …)?

Edit: and test the behavior on X11 and if you get the same problem there to flip the prime-sync setting.
At least it will tell us whether we're looking at the right problem.

Last edited by seth (2025-06-28 16:28:43)

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