I started getting freezes where the last frame on screen stays and the fans slowly speed up. Reset button has no effect and only holding the power button shuts the pc off. I tried another PSU and with and without discrete card. GPU is not actually getting detected at all in Windows. Running CPU stress test freezes within seconds. Power at the wall exceeds 100W at the time of the crash so it seems power related. RAM test didn't detect any issues.
Possible heat damage
Several weeks ago I had a water cooler failure which caused the cpu to heat up presumably over 100C several times until I realised what the issue was.
What is the likely cause? Damaged CPU or Motherboard? Is there anything can be done to find out? Unfortunately I don't have compatible CPU to test the MOBO.