Pc restarts to lock screen under any load

[RSRVisuals]

I just picked up a used 980ti on facebook marketplace + a new psu to match and now whenever i run any sort of benchmark or intense game the screen goes black for a sec, then restarts to lockscreen. The seller couldnt test the card so i got it cheap (£50), but prior to upgrading i had no issues at all similar.

 

Pc specs are

Win10 64bit, latest update

cant find a motherboard name but its from a lenovo e73 thinkstation, intel H81 chipset

i5-4690

2x4gb samsung ram sticks at 1600mhz

Reference 980ti, ive tried underclocking memory and power limit

Kingston a400 240gb sata ssd

WD Blue 500gb hardrive

EVGA 650bq psu

[LomaFin]

Sounds like a PSU problem to me, but if you just got a new PSU too its a bit weird. Is it preowned or fully new? if it is fully new it might be faulty? You could try the GPU in a another system and see what happens

[RSRVisuals]

7 minutes ago, LomaFin said:

Sounds like a PSU problem to me, but if you just got a new PSU too its a bit weird. Is it preowned or fully new? if it is fully new it might be faulty? You could try the GPU in a another system and see what happens

Psu is brand new from amazon, i dont have another system with a strong enough psu to run it