Bug #357

FPS Drastic Drop After 30 Minutes of Gameplay

Status:	Closed
Priority:	High
Added by:	DRG linux on February 20, '25
Assigned to:
Due date:
Reported for:	S05.07

Steps to Reproduce

1. Launch the game in proton compatibility mode (regardless of proton version)
2. Play without any issue during around half an hour
3. No matter what happens on screen, even if you're at the base, the problem is triggered
4. exit the game completely
5. return step 1

Explanation

A weird problem with fps dropping after about 30 minutes of play.

Indeed, I can play without any problem for about half an hour, entering the rig and then launching the mission.
If the mission lasts less than half an hour, the problem is triggered in the next mission or in the rig before the next mission.
Once the problem is triggered, the only way to resolve it is to simply quit the game, then restart it, and you're back in a “30-minute state of grace”.

Once the problem is triggered, the screen suffers from stuttering, with fps dropping most of the time if you move the camera, then rising again when you don't move the camera. So its very anoying to play with this stutter/lag visual experience.

For example, with a 75 Hz screen, if you set the max fps to 75, no matter what happens on screen, if you don't move the camera the fps remain at 75. But as soon as you move the mouse and therefore the camera, the fps drop to “a so-called around 40”. i.e. around 35 fps less.
If I don't set the fps cap, I'm running at around 150-200 fps, but when the problem is triggered, the drop is much greater, almost 90 fps less.
Another thing : when the problem is triggered, I can ride the pipes without any drop in fps (but still without moving the camera via the mouse).

Another point to note is that the problem is triggered in both single-player and multiplayer mode.
In multiplayer mode, the problem is triggered regardless of the host server machine (Windows or Linux). And interestingly, the problem triggers almost simultaneously with another linux computer (with different hardware settings) connected to the same game.

The game runs via steam in proton compatibility mode (regardless of version or experimental) on a linux operating system (arch linux based with the latest 6.12 LTS kernel, but the problem also occurs on other distros such as debian based and with NVIDIA GPU)

CPU : ryzen 5700X
GPU : RX 6600 (8G VRAM)
RAM : 32 GB

I've tried various settings gleaned from the forums, such as :

change DX11/12/safe mode version
change proton version (7.06/8.0/9.x/experimental)
change steam launch options: -notexturestreaming

engine.ini parameters :
bDisableMasterEQ=True

r.MotionBlur.Max=0
r.MotionBlurQuality=0
r.DefaultFeature.MotionBlur=0
r.DepthOfFieldQuality=0
r.PostProcessAAQuality=0
r.DefaultFeature.AntiAliasing=0
r.SceneColorFringe.Max=0
r.SceneColorFringeQuality=0
r.Tonemapper.GrainQuantization=0
r.Tonemapper.Quality=0
r.LensFlareQuality=0
r.DefaultFeature.LensFlare=0
r.DefaultFeature.Bloom=0
r.BloomQuality=0
r.Shadow.MaxResolution=704

r.AmbientOcclusionLevels=0

check CPU/GPU temperature (around 50°C)
check driver version (everything is uptodate)

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