>fan gets louder the slower it goes

>>62347011
It's probably only more apparently louder because it either enters into a frequency range without competing noises to drown it out or your brain doesn't adapt to the more infrequent revolutions and you are more attentive to it. It's physically impossible for it to generate more db by going slower, it's all to do with your perception.

>>62347011
fan at lower speeds vibrates at resonating frecuency of computer case
solution: force fan into higher speeds and enjoy cooler cpu