which ones? the CM or the after market? the CM fans at 100% do not seem to move as much as these after market fans. at the time though, i was looking for the cheapest , highest CFM fans w/ free shipping i could find, lol... im cheap, cant lie. http://www.newegg.com/Product/Product.aspx?Item=N82E16811999479
having now looked up this fan again, it runs at 39dba, no wonder the CM fans seem so much more quiet! if i run these fans on 60-70% i cant really hear them, if i run them at 100%, they hum and whine like no other. but, you can feel the air just bellowing out.