@Pinhedd what 79xx card are you using and did you overclock it?
Two Gigabyte 7970s with Windforce 3 coolers, factory overclocked to 1000Mhz. I overclocked them an additional 100Mhz to 1100 and brought the memory up to 1400. I'm sure that I could go higher but those things put out a lot of heat. Right now it's like having a space heater in my bedroom and its the middle of summer here in southern Ontario. Even my 8000 BTU in room air conditioner and house's air conditioner can barely keep up with it.