Don't know how to help, it works like a charm for me. If it's any help my specs are:

i7  860 @3,6 ghz
p7p55d evo
8gb ram
2x MSI 750 Ti
2x Gygabite 750 oc
gtx 670
Corsair hx850

+latest drivers
+pciex 16 to 1x risers, powered

The 750's have a pciex power of their own while the powered risers don't do anything for my Ti's. They are just plain rotten.