I think you're going to need a special power supply, I don't think plugging two 4-pin connectors in will work. I've seen this before on older Tyan server boards, they had 8-pin connector and was very picky about which PSU you used.
I have an Abit board which also has the LED display on it for bios codes. On mine, FF also meant 'boot attempt', a normal code. I don't have FB in my manual, but all my F* codes were power related. Judging from what everyone else has been saying, I'll agree that this sounds power related.
Look for an EPS12v power supply instead of an ATX12v
Blah, just read your last message, EVGA says it's not a power-related issue? If you lived in my town, I know a great shop that would test different ram and PSUs with your board for free.