Last time I tried to play Stray on Linux Mint on my laptop while connected to 4k TV, I ran into severe degradation unrelated to thermal throttling. I had to tweak the resolution down a lot and even the graphics. I recently went back to using Windows on the laptop because of an unrelated network speed unreliability problem on Mint, and when I tried Stray, there were no issues. Before this, I had even installed Stray on my gaming PC to stream from the laptop because of how laggy the performance was.
Specs
RTX 3080-Ti Laptop AMD Ryzen 9 6900 HX Linux Mint latest 16GB RAM
EDIT:
Okay so I suspected it was thermal throttling, even though I have a cooling fan. Turns out not using a cooling fan is better than using a cooling fan at the lowest setting. At the highest setting, the cooling fan is too loud but the game performs still slightly worse than on Windows.
If I understand correctly, does that mean you had two GPUs in the system? (Integrated GPU in the AMD chip + a separate NVIDIA GPU?) If so, were you maybe running on the wrong GPU? Also, did you install the NVIDIA proprietary drivers or just use the out-of-the-box open stuff? For NVIDIA usually you want the proprietary ones, and for AMD open is fine, but the kernel you’re running really matters in my experience…
You can check whether the game is running on your main GPU with “nvidia-smi”. Assuming you’re running proprietary drivers