It is passive at first and doesnt even come on most of the time while doing light tasks. Playing tablet-style games or content-rich websites will make it come on somethings, but so quiet you dont hear it unless you are in a very, very quiet room. By hear, I mean it is practically nothing. When playing heavy games, heavy programs, etc., it will variably spin up to a max speed. At that max, you will know it is on, but still not loud. I have had some loud laptop fans in the past. This one is not loud. This was a major sticking point for me. I am totally ok with this one. Other 2 in 1's have much louder fans than this one.