Big Picture (on Desktop) Causes Launched Games to Experience ~20+ Frame Drops

[ThisNekoGuy]

Your system information

• Steam client version (build number or date): 1726604483
• Linux Distribution: Gentoo (LLVM18-built, and with glibc & libc++)
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes
• Steam Logs: steam-logs.tar.gz
• Kernel: 6.10.9-tkg-eevdf-gentoo-llvm18-generic_v3
• CPU: Ryzen 7 3700X @ 4.05 GHz
• RAM: 32GBs @ 3600 MHz
• GPU: AMD RX 7800 XT
• GPU Driver: Mesa 24.2.3 (radv)
• Display Resolution: 2160p (4K)

Please describe your issue in as much detail as possible:

After opening a terminal and running steam with steam -bigpicture, games launched afterwards suffer a loss of at least 20 frames for some reason.

In my case, I used gamescope (version 3.15.5, and not on the client itself) for the games I've launched to use (tested with both Final Fantasy XIV and Hogwarts Legacy) and both received noticeable framerate drops simply from having Steam be in bigpicture mode. This doesn't happen otherwise. And for Hogwarts Legacy, in particular, moving the mouse (via controller for me) with this setup, specifically, causes sporadic "static TV" artifacts to appear every time the cursor is moved at the main menu. I would actually screenshot this artifacting but it flickers and is really hard to catch, and attempting to record it with KDE's Spectacle software makes Spectacle segfault for me...

And to clarify, this is not quite the same issue as:

• https://github.com/ValveSoftware/steam-for-linux/issues/11255

because this isn't about the client itself, but rather its sub-processes. Big Picture otherwise seems to behave fine as long as Steam is launched using -bigpicture.

Ideally, I would like for big picture mode to not have a performance impact on my games... Especially when the target framerate is 60Hz, which isn't a particularly high bar for desktops...

Steps for reproducing this issue:

1. Launch a KDE Plasma 6 session
2. Open a terminal
3. Run steam -bigpicture
4. Connect a controller (Optional, but I connected a PS4 controller)
5. Launch a game (I used Proton 9.0-3)
6. If using gamescope, set to 4K dimensions (in this test case; for Hogwarts Legacy, I actually ran gamescope from a terminal and used DISPLAY=:1 as an advanced launch option to work around the game possibly hanging at launch)
7. Attempt to play the game (with the framerate indicator on in the Steam Overlay to measure the loss)

[ThisNekoGuy]

@kisak-valve Just to clarify, why is this labeled with 3rd party game? Everything I mentioned is a title on Steam, the only exception being gamescope which isn't a game... it's Valve software. Also, the overlay isn't strictly required to reproduce this...

[kisak-valve]

Hello @ThisNekoGuy, for transparency, that label was added because the emphasis of this issue appears to be on game performance, not Big Picture Mode performance, and the Steam overlay might be involved, but that part is less clear.

[ThisNekoGuy]

Oh, okay. I was mainly under the impression of 3rd party game just meaning "not a game on Steam / non-Steam game," so I was confused; thanks for clarifying that and the other stuff :+1: