That fan was 120MM. I would recommend a high static pressure fan in push. Since it's pretty much right against the back of the motherboard, the static pressure will keep a good volume of air moving across the whole motherboard.
I can't find the pics now, but for the X79 Motherboards, they even go as far as putting little heat sinks on the mosfets and areas around the socket.
Edited by ComputerRestore - 5/26/13 at 6:24am