RX480 Rig Crashing

I have a new RX480 rig that crashes whenever I put more than 1 graphics card in. I startup claymore dual miner in either single or dual mining mode, and it crashes the whole computer. I can hash on 1 card just fine. Does anyone have any tips or anything I could try? I have tried it with stock wattman settings, and the latest 16.8.2 driver, and 16.7.2 driver.

Specs:
Biostar hi-fi H81S2
Celeron
4gb ram
RX480
120GB SSD HD
Windows 7 Pro