I've seen instability on my computer that fits this as well, where if Firefox Nightly had been running for more than a day my PC gaming framerates would sometimes be terrible (120->30) until I minimized all desktop windows (and could then unminimize them again and it would be okay), or restarted Firefox. Updating ANGLE isn't an easy option as it takes a couple weeks of solid effort, so we'll be looking for more timely mitigations while considering that.
Bug 1962210 Comment 4 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
I've seen instability on my computer that fits this as well, where if Firefox Nightly had been running for more than a day my PC gaming framerates would sometimes be terrible (120->30) until I minimized all desktop windows (and could then unminimize them again and it would be okay), or restarted Firefox, if I didn't do either of those things then eventually the monitors would turn off and the computer would reboot, which seems to happen a lot sooner (within a few hours) if I have two USB audio devices connected (normally I have a Schitt Hel2 with headphones plugged into it, but when I also plug in a Focusrite Solo with no instrument plugged into it, my computer tends to freeze like that and reboot within a few hours every time - I am not sure how USB audio is involved). Updating ANGLE isn't an easy option as it takes a couple weeks of solid effort, so we'll be looking for more timely mitigations while considering that.