I recently upgraded to the be quiet silent base 600, and it has a manual system fan controller on it. My problem is that I don't know if it is working properly. When i switch the speed i don't really feel a difference in air speed if i put my hand behind the rear exhaust fan, which is the default silent wings 2 fan, and I can't tell a difference in noise. Is there any way i could guarantee that the 3 speed fan controller works?