not all of them work. I know the popular ones like the ninja, freezer 64 pro and si-120 DO NOT work, but you can buy a bracket for like $5 that will allow it to fit. This will decrease the amount of room between the hsf and the side of your case so make sure you have enough room to do so b4 you get it. There is also an am2 zalman c9500 but it's very expensive @ $61.