Took a quick shot of the innards.
If you look closely you can spot the 140mm fan I mounted on the back of the case to help exhaust air from the cards. Put it on there when I had three GTX580s. It works really well.
You can also spot the 4-pin molex connector I soldered to the motherboard to provide extra +12V PCI-E power. The Asus P9X79 Deluxe doesn't have one built onto the motherboard, so I had to put one on there myself.