Trying to fix my my relatives PC.... System randomly freezes even just on the desktop, and when gaming randomly freezes , reboots, crashes, sometimes after automatic reboot after crash the bios does not act correctly and hangs and you have to flip the power switch off on the PSU and back on to restart...happen on original board and new board I swapped in... I5 6600 (non-k) 16gb corsair ballstic 2400 @ 2133 asrock b250 pro 4 sandisk 240gb ssd + Hitachi ultrastar 2TB Sapphire rx480 Nitro+ windows 10 home This is not making any sense to me. And I'm beating my head trying to figure out what is causing this . *CPU passes Intel Processor Diagnostic Tool , temps are fine (using aftermarket heatpipe cooler) *Memory passes Windows memory tests memtest 86, still tried uping the voltage a little and testing system stability again... no effect have ran several times have had the system freeze a couple times while testing, but it should not be able to pass just fine on other attempts…. *POWER Supply 650 Watts is more then what is needed, has been swapped out with known good PSU no effect * msi h110m Motherboard swapped with a asrock b250 pro 4 board no effect, latest bios and all that... *sandisk ssd / and 2tb hitchi ultra star appear fine, windows 10 home formated reinstalled, all the lastest drivers *swapped my MSI rx480 for his sapphire RX480 nitro, no effect can play TF2 for 15 minutes or 3+ hours just fine before there is a problem, seems completely random, I’ve found the system will not last 5 minutes using FurMark stress test Pulling my hair out…. Think I Figured it out! looks like its has to be the memory, put a new kit of dd4 in that I had picked up and its at 30+ minutes and counting in Furmark, h Now how in the heck does memory causing the issue pass memtest 86 and windows memory tests?