I have four 120mm fans, and that was really slow me too loud. No matter how "Silent" these things are, they make noise !! And a big fan is just inherently quieter by the slower speed !!! This really makes a lot. And the room temperatures also remains much further in the basement !! The thing is a lot more air to the two small, and just much quieter !! I really do not listen to the fan. and I saw him not even to ner control, it runs at the moment so the "top speed". So I can only recommend to everyone !!!