My son Ryan and I found out today that Crossfireing 2 6870's with only a 750 watt power supply is a bad idea. It was up and running like a house on fire until I noticed that the temps on the gpu's were 61c and 84c I shut windows down and asked Ryan to pull the power cable out of the back of the machine so I could pull the hot gpu and I was going to clean it and put some arctic silver 5 on the cpu. When he grabbed the power cable running from the wall socket to the power supply it was so hot it left a mark on his hand! The second gpu wasn't pulling the power it needed and was in the process of frying the whole setup. So we're just going to scatter them over various machines and not order any more. They sure do suck the power.