I'm facing this problem since November,
My pc restarts when i try to export 8k texture out of substance painter, but didn't cause any restart during benchmarks,
But now yesterday it restarted during gaming and benchmarks, i ran OCCT with Shader complexcity 1/2/8, it restarted instantly,
Also...
I'm running Rx 590 with thermaltake Smart modu 630W
It's been 1year that i upgraded my gpu and psu.
I don't thing I ever faced this kind of problem before.
When I work with the scene in blender eevee with volumetric tiles size 2px and export 8k maps from substance painter with filter turned on...