I received two of these today. I'm planning on using them as the top exhaust fans in a Lian-Li PC-75 once all the parts for the install get here. I did hook them up to the rear Molex plug on an Antec TC550 to test them out. They're relatively quiet, but not overly so, and they develop enough rotational torque to forcefully wiggle in my hand while I was holding them. I don't recommend them as CPU fans, though, as their metal construction makes them weigh about a pound (!) a piece.