for a large number of other reports indicating the same symptoms described in this report.
Game
• Warhammer 40,000: Space Marine 2
• Regression introduced after Update 11
• Prior to Update 11, the game ran flawlessly under Proton on this system.
Symptoms
Description of the Problem
After Update 11, the game exhibits periodic main-thread stalls during missions when Easy Anti-Cheat (EAC) is enabled under Proton.
Observed behavior:
• Frequency: every ~30 seconds to 2 minutes
• Duration: typically 1–4 seconds (after mitigation)
• FPS drops to ~15–20 during stalls
• Complete input stall during events (mouse and keyboard unresponsive)
• GPU utilization drops during stalls but appears secondary
Disabling EAC removes the issue entirely, but there is no way to save progression in-game with EAC disabled so this is not an ideal solution.
Mitigation Findings
• CPU saturation significantly worsens stall severity
• Applying systemd CPUQuota reshapes behavior:
◦ Stall severity and duration are reduced
◦ Stall frequency increases
• Disabling frame generation removes input lag but does not remove stalls
• Alt+Enter temporarily clears the stall
• GPU-side mitigations do not resolve the issue
This strongly suggests a periodic EAC-related memory or synchronization operation blocking the game’s main thread, likely introduced by Update 11’s “memory handling improvements”.
Reproduction
Reproduction Steps
1. Launch Space Marine 2 under Proton with EAC enabled
2. Enter any mission, play through mission.
3. Observe periodic stalls during gameplay
Compatibility Report
System Information
I confirm:
steam-2183900.log
Also, as a point of note, see
https://www.protondb.com/search?q=space marine 2
for a large number of other reports indicating the same symptoms described in this report.
Game
• Warhammer 40,000: Space Marine 2
• Regression introduced after Update 11
• Prior to Update 11, the game ran flawlessly under Proton on this system.
Symptoms
Description of the Problem
After Update 11, the game exhibits periodic main-thread stalls during missions when Easy Anti-Cheat (EAC) is enabled under Proton.
Observed behavior:
• Frequency: every ~30 seconds to 2 minutes
• Duration: typically 1–4 seconds (after mitigation)
• FPS drops to ~15–20 during stalls
• Complete input stall during events (mouse and keyboard unresponsive)
• GPU utilization drops during stalls but appears secondary
Disabling EAC removes the issue entirely, but there is no way to save progression in-game with EAC disabled so this is not an ideal solution.
Mitigation Findings
• CPU saturation significantly worsens stall severity
• Applying systemd CPUQuota reshapes behavior:
◦ Stall severity and duration are reduced
◦ Stall frequency increases
• Disabling frame generation removes input lag but does not remove stalls
• Alt+Enter temporarily clears the stall
• GPU-side mitigations do not resolve the issue
This strongly suggests a periodic EAC-related memory or synchronization operation blocking the game’s main thread, likely introduced by Update 11’s “memory handling improvements”.
Reproduction
Reproduction Steps
1. Launch Space Marine 2 under Proton with EAC enabled
2. Enter any mission, play through mission.
3. Observe periodic stalls during gameplay