Memory leak like bug - need help troubleshooting

[Latecloser]

Compatibility Report

• Name of the game with compatibility issues: Overwatch 2
• Steam AppID of the game: 2357570

System Information

• GPU: Nvidia GeForce RTX 3080 Ti
• Video driver version: 565.77
• Kernel version: 6.12.11-200
• Link to full system information report as Gist:
• Proton version: 9.0-4, 8, and Experimental, possibly all versions

I confirm:

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

Symptoms

The game plays perfectly, for a bit. It varies some, but rather consistently after 2-3, sometimes 4 matches the frame rate drops drastically. It appears to drop down to 20-30ish when it's normally holding 165 easily (syncing to refresh rate of monitor). If my character stands still, the frame rate appears normal. Any movement makes it drop.

I have tried to isolate if any setting contributes to it, but it does not appear to be so. Whether I run the game at the highest settings or the lowest, or in between, lowering or disabling any setting individually, matters not. The behavior is the same.

The only way to get things back to normal, is to exit the game and restart it. Upon which, everything works again. Until, enough time goes by that it happens again.

Initially, I wondered if it was some kind of thermal issue, but it does not appear to be so. The game doesn't tax my system much.

The issue also does not appear to be specific to Overwatch 2. I get the same behavior in other games. I play Path of Exile 2 and the same thing occurs. So, I can't tell if this is a proton bug, a driver bug, some other library or something specific to my system.

I would like to troubleshoot the issue further, but I can't come up with anything else to try. This issue also, did not used to happen. It's existed for months. Previously, things worked fine. I can't recall for how long it's been occurring. I'm sure it's less than a year, but it's definitely been happening for a few months, possibly several. Something changed. The only changes to my system in that time period has been hardware wise, a new monitor and switching to 1440p resolution. I did try switching to lower resolution and the issue still occurred.

Fedora 41 is my distro and it updates software frequently, so that complicates the possibilities. Using X, instead of Wayland. AMD Ryzen™ 9 5900X processor with 32 GB of RAM.

Reproduction

Play game, after certain amount of time, frame rate drops drastically. Happens every time, easily reproducible.