Question Every game that i play constantly crashes and i dont know what to try anymore

[NovaDryft]

Pc Specs: Win 10 64 bit
zotac gtx 1080ti
16gb ddr4 tridentZ ram
i7 8700k cpu
gygabyte z390-ud motherboard

So i have been having problems with this for multiple months but now decided to go more into it. I have been experiencing crashes to desktop and sometimes freezes to the point where i need to unplug my pc for a while now and i dont know what to do. Ive tried resetting my pc completely multiple times and installed newest windows updates and graphics drivers.

 

[rgd1101]

make and model of the psu?

run memory test?
cpu/gpu temp and usage during the game?

 

[NovaDryft]

the temp is on 78 degrees celcius maximum and usage on 70 % maximum too and also how do i run a memory test?