PC instant shutdown on furmark, hitman bench,heaven bench


Oct 29, 2017
hello guys before 5 days i build a new pc my self

specs :
asus prime x370 pro
ryzen 5 1600 3.7 OC
sapphire vega 56
16g ram crucial ballistix sport 2933OC
corsair vengeance 650m

at the beginning everything was fine except the psu made a sound from the cooling fan but it stopped.
now i did tried some bench and everything was fine but after some hours my computer started to shutdown on bench marks.
on vega balance mode and turbo mode my pc crashed on furmark the moment i started the bench same thing happened after i tried hitman benchmark and heaven bench. now i found a solution if i set my card to power saver mode or reduce the volt from wattman at least 100mv the problems seems to go away
else with stock settings pc crash and i need to off/on the PSU button to be able to start my computer again.

i did check for temps and everything was good i even set the vega fans to 4k rpm but it didnt changed anything.
i also checked the psu for temps but it was not hot and the fan seems to work okey
and i tried the dual bios from vega witch made no difference

im suspecting my PSU its faulty what do you guys think ?