P5b deluxe and HD 4870

I just got a new HD 4870 and its not working. The first one I got i used my Ultra X2 PSU 550 watt. It had two PCI-E connectors so I thought it would work. So when I installed the card and I had the fan spin up and my monitor be blank, I thought it was DOA. So we I got the replacement and had the same problem, I thought it had to have been the PSU. The Ultra X2 uses a duel 12v rail and it looks like it does not push enough amps. So I got a Antec "true power" TP-750 watt and tired it with that, still no video output. I have a 8800 that works just fine in the same slot. My question is, could it be my P5B delux mobo? I will try hooking up the Antec PSU differently, adding some PCI-E connects on the extra rails to see if that helps.

That seems possible, I will try it in another system with the same PSU, cause if it is DOA, then it would be the second one that I got that way. Unlikely, but possible.