I have the Powercolor AX7950 GPUs with a 1600W LEPA PSU and the Gigabyte 990FX UD-5 motherboard. With a Kill-A-Watt hooked up to it, I see a power draw on it of about 1400W. Maybe that was when I had powertune at +20 on it though? I'm redoing that board now as we speak (bringing it up to Windows 8 instead of Windows 7) and won't be having powertune on it this next time. I'll report back once it is up and running. Swapping out standard risers for powered risers to see if the kH/s goes up some with non-powertuned settings. Then I'll attempt to add a 6th card into the PCI-e 1x slot (I have a 1x->x16 riser) if all goes well.

This milk crate is getting tight on space! :p