I suppose "GPU lockup CP stall / GPU resets over and over" is probably such a
generic error that a lot of bugs could be reported without having anything to
do with each other, but FWIW, I recently experienced exactly the same error
shortly, usually < 30 seconds, after starting any 3d-accelerated game.
I tried 3.5.7 and 3.6.11, had the same result, search around for more info,
ended up in this issue, tried installing 3.8.0-rc4, and voila, problem is gone.

I guess this means it's not interesting with a bisect, but I'm willing to try
if it helps in any way.