When using any enhancement (such as Nyx Fast) during the conversion it will hard lock the PC, no mouse / keyboard response CTRL+ALT+DEL has no effect, have to press the reset button directly.
No overclock it’s an X3D Chip, PSU is 1200W Corsair
But that said it’s not Topaz AI. Going trough the event logs, found some details. The drivers for GPU kept crashing. Did some more testing soon as any load on the GPU crash (the 7900XTX the Arc is just for QuickSync) DDU the drivers, and even before I can reinstall crash crash crash. Swap for a 4060Ti I had around and everything works. Looks like the GPU died.