Computer crash (black screen) at random times

[youwepapa]

Help, my computer has been black screening for the past year. Usually during gaming, but has crashed on windows login screen before.

specs:

Windows 10 Pro 64bit

X79 Sabertooth

i7 4820K (liquid cooled with H100)

24GB ddr3 Corsair vengeance 

GTX 1080Ti evga black edition

1200W Corsair PSU

cpu temp idle: 45c

cpu temp under load: 50c

Gpu temp idle: 37c

gpu temp under load: 49c

 

things I’ve tried multiple times:

turn it off and on again lol

reinstall windows

full disassemble and reassemble (cleaning and checking for hardware damages, no damages found)

bios reset

run memtest (no failures found)

reapply thermal paste

reseat ram 

Change GPU (gtx 560, 780ti, 1080ti, and Rtx 2080ti) all resulted in random black screens

reinstall drivers (fresh install after fresh windows)

changed monitors (maybe 4K was too high, but 1080p resulted in random black screens as well)

underclock everything in the pc

over volt everything in the pc

swapping storage devices (4 different SSDs, 3 Different HDDs)

 

at this point I don’t know what else I can do to fix this problem, I don’t have money to buy a new pc. I need this pc for work. But I can’t work if it keeps crashing.

can someone tell me what I missed?

 

i cannot find a way to consistently cause the pc the crash. every time it crashes during a benchmark, the next time it gets to that part, it wouldn’t crash.

 

also in task manager it always says my bios time is 10000+ seconds, even though it takes 30 seconds to boot in to windows.