Miner Freeze with 4th Card

Hey all - running the following:
BTC Pro H81
2 x 4GB Kingston Fury RAM
4 x R9 380 OC Edition Cards
Windows 10 on ethermine.org pool using claymore

Now everything sweet with 3 cards. However when I plug in the 4th card. Starts fine. After 30 seconds. Screen freezes. Cannot even CLT ALT DEL have to do a hard reset.

Tried different riser cards
Tried different cards

Still no luck