Hello @Krutonium, we're tracking issues with games run with Proton in the Proton issue tracker. Also, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/37#issuecomment-1382737727.
Your system information
Please describe your issue in as much detail as possible:
I went to play GTA V, ran the setup, and the setup just ran for ages. Eventually my system started stuttering hard, so I opened System Monitor and well, yeah.
Steps for reproducing this issue: