Is that a dedicated mining computer?
Here is what worked for me:
-snip-
yes its a dedicated rig.. My first one.. Thus the reason why it looks nice.. haha
But anyways what cards you using? And what program you using to OC?
Remove the crossfire connectors
CGMiner 2.11.4
Windows 7 Ultimate x64
Catalyst 13.3 with included SDK
MSI Afterburner 3.0.0 Beta 8 (Easily allows unofficial overclocking)