I recently built my pc with few used parts and few brand new it seems to have an unknown issue where it keeps crashing randomly without any pattern and i have not been able to recreate the issue with defined steps. One time i was randomly able to crash it when messing with gpu setting. Managed to do it twice

The crash: pc crash in unique way it crashes stops taking inputs from mouse and keyboard to the point that both devices light go off. There is no blue screen or anything it shows the screen that last being shown before crash. Pc still operates and does not reset automatically i have to hold power button to shut it off.

Parts: AsRock Motherboard DDR3 RAM (NEW) ( had to replace cell on new motherboard as date was resetting back to 2016) INTEL I5-65300 (SOURCED FROM MY WORKING OLD PC) 650 W POWER SUPPLY (NEW) 16 GB RAM (USED) 256 SSD FENGSHEN (USED) 128 SSD KINGSTON (SOURCED FROM MY WORKING PC) AMD RX 590 8GB RAM (USED)

TESTING: Gpu stress testing using FurMark Software 20 Min test. Worked fine no crash no fram drop. Avg fps 67 (monitor 60hz) Cinebench CPU stress test 10 min, 15 min stress test no crash Ram testing MEMTEST86 full course testing no crash or faults found. CrystalDisk All SSD and HDD in 100% health

Dont know what to do about it. Any help would be tremendous help

Update:

PSU is 600W algo warrior AK 600

Motherboard is ASRock Z170A-X1/3.1