MiningRig Shutdown and Restart problem.. [HELP!]

Hey guys so I've finished my rigg and trying to start mining.

I open NiceHash and the system can see all the 4 gpu's perfectly but When I start mining the system shuts down and restarts. I don't know what the problem is. If I use 3 gpu's it shuts down again. If I use 2 gpu's it will start to mine but shutdown after a while. Funny thing is that , the first time I started the rig for mining with 4 gpu's system mined for 20 minutes no problem with high OC. I don't know what is wrong. I have tried =>

-) No OC, just go stock.
-) Lower power of the GPU's to %50 - %60
-) increased virtual memory ram
-) PCI Gen 2 - Gen 1
-) Decoding 4 active
-) Bios Update
-) Windows Update
-) Checked all the power cabes.
-) Switched the PCI slots

SYSTEM SPECS =>

-) x4 Asus Strix OC 1070 8 GB
-) 8 GB 2400 Mhz Vengeance Ram
-) intel Pentium G4600 CPU
-) 240 GB Kingston SSD
-) AeroCool 850W +80 Platinum PSU
-) MSI Z170 PC Mate

Topic: MiningRig Shutdown and Restart problem.. [HELP!] (Read 127 times)