I recently made a new build as follows:
Processor: core i5 6500k
Ram: 16gb hyper x ddr4
SSD: 180 GB Corsair
Motherboard: MSI z170a SLI Plus ( this is the second board i have tried)
GPU: 2x RX 480 crossfire XFX Black OC edition
PSU: Thermaltake 850w (also swapped out for a 750w same problem persisted)
Problem: Computer randomly restarts. No BSOD. A very generic error is supplied. Kernel 41. Loss of power, unexpected shutdown.
Troubleshoot: I have replaced the motherboard. I have tried a separate 750w PSU. I have ran two mem tests and I have ran the intel cpu diagnostic utility which both have came up clean.
Weirdness to take into account: One rx480 works fine on my old MSI board/PC. Although I cannot run two because this old cpu cannot handle both gpu's, i feel that they would run fine without crashing. On the first board that i returned it ran fine for 3 days and then just started restarting left and right with the same kernel power 41 error. The second board i got did the same thing. I ran overwatch on high settings all weekend without a crash. Then randomly while searching the net it started crashing every 4 minutes. When I reinstall the AMD radeon drivers it seems to stave off the crashing but only for so long.... I would love for AMD to address this issue. I don't know what else to try other than returning the cpu and or trying one stick of ram at a time. I have now just enabled compatibility settings on the cards and it crashed right after.