Reversing drivers didn't fix it.
Completely removing all nvidia drivers and reinstalling them fresh didn't fix it.
I remember when the weather got hot last year my GPU went to ***and I removed the back plate and plastered it in thermal paste and it made it run beautifully. Can't really be bothered to do that again yet.
Tried limiting the power to 70% and temp to 70 degrees max and it seemed stable but crashed.
I guess the GPU might need binning but I'll try a full fresh windows install to try and work out if it is just driver related.