you do not talk about the powersupply in your quote.
IT's important and you need at least a 1000W high quality to be safe. 3 * 250W + 100W + margin
Vendor said it was 870w @ wall plug
People always overestimate power supply for some reason. I have 2x7970 and 1x7950 running on an 850W PSU (pulling ~880W from the wall).
I thought BAMT didn't support 79xx cards though?