Doom 3.

[dmxdex2020]

I ran OCCT for 30 mins it came back stable.

 

[jak731]

Linpack is a good stress testing tool, tends to get cpus around 5-10 degrees hotter than orthos or occt, good example on the graph halfway down this page.

The probems you describe do sound like stability problems, have you tried running furmark on your graphics card?

 

[memphisto]

it sounds like yer graphics cards borked to me if youve tried all the above and are still having issues.