They are in the direction of push to force more air over the heatsink. They are 252CFM fans I bought from newegg. http://www.newegg.com/Product/Product.aspx?Item=N82E16835706015&cm_re=252_cfm_case_fan-_-35-706-015-_-Product They are very loud, but bring the temps to around a constant 35C - 45C running at 325MHZ. Ive never seen any of them hit 50C . I want to extend the life of these as much as possible. When I put my hand behind one of the cubes the heat feels like a hairdryer on "high". That tells me massive heat is being removed, and heat is the #1 killer of electronics.

Vegas