At one time I had a BIG HD 7950 and a 7790 in a Dell 5500 case. The PSU has plenty of overhead, you just have to use SATA to PCIex power adapters. I don't recommend pairing a big GPU in these cases, but I have a 960 + 750Ti that runs fine even in a non-air conditioned space. My other T5500 has a reference 7970... runs just fine.