Compatibility Report

• Name of the game with compatibility issues: The Elder Scrolls Online
• Steam AppID of the game: 306130

System Information

• GPU: AMD Radeon RX 9070 XT
• Video driver version: Mesa 26.2.1-arch1.1
• Kernel version: 7.1.9-zen1-2-zen
• Link to full system information report as Gist: https://gist.github.com/elthaslynx/392188ad2bc7b4b8309ad18faab881e8
  (includes Steam Runtime Diagnostics; report is in German)
• Proton version: Proton Experimental (also reproducible with GE-Proton 11-5)

I confirm:

• [x] that I haven't found an existing compatibility report for this game.
• [x] that I have checked whether there are updates for my system available.

PROTON_LOG attached: https://gist.github.com/elthaslynx/0745988cf36e130ebf6086d3d28cf80b
(xz-compressed, ~30 MB)

Symptoms

FPS roughly halves as soon as the game window has input focus, compared to
when it doesn't. This happens consistently with Proton Experimental and
with GE-Proton 11-5, but NOT with Proton stable 11.0-2, which runs
unthrottled regardless of focus state.

Example (MangoHud, native Wayland via PROTON_ENABLE_WAYLAND=1):

• Focused: ~50-67 FPS (avg 45, 1% low 13), GPU load ~52%, CPU load ~14-16%
• Unfocused (e.g. after pressing Super to open the KDE app launcher,
  character standing still either way): ~100 FPS, GPU load ~70%

Also reproducible with Proton Experimental launched directly through Steam
(no gamescope, no HDR involved) — same focus-dependent halving.

The following were ruled out as the cause during testing:

• Sync method: identical behavior with NTSync and with PROTON_NO_NTSYNC=1
  (forcing Fsync)
• KWin Direct Scanout: identical behavior with KWIN_DRM_NO_DIRECT_SCANOUT=1
• Adaptive Sync / VRR mode: identical behavior with KDE's Adaptive Sync set
  to "Automatic" vs "Always"
• Present Mode (as reported by MangoHud) is identical
  (SHARED_DEMAND_REFRESH) in both the fast and slow case
• Mouse pointer confinement/mouselook: releasing the cursor lock in-game
  (ESO's "." key) while still focused does not restore full FPS
• Not gamescope-specific: reproducible both with and without gamescope

Reproduction

1. Launch The Elder Scrolls Online via Proton Experimental (Steam launch
   options: MANGOHUD=1 %command% is enough to reproduce; HDR/gamescope
   are not required).
2. Observe FPS via MangoHud while the game window has focus.
3. Move focus away from the game window (e.g. press Super to open the KDE
   application launcher, or Alt+Tab to another window) without pausing or
   otherwise interacting with the game.
4. Observe FPS via MangoHud rise noticeably (roughly doubles in my testing)
   while unfocused.
5. Return focus to the game window; FPS drops back down again.
6. Repeat with Proton stable 11.0-2: FPS stays consistent regardless of
   focus state.

Timeline of the attached PROTON_LOG

(approximate, timestamps relative to process/log start)

• 0:00–0:15 loading to main menu
• 0:15–1:05 loading character into world
• 1:05–1:21 idle, game window FOCUSED (slow FPS)
• 1:21–1:36 idle, game window UNFOCUSED (Super key pressed, FPS unthrottled)
• 1:36–1:51 idle, game window FOCUSED again (slow FPS again)