I have (as some here) fan my Corsair H110 exchanged for the NF-A14 PWM and am very satisfied. Have had run into vertical position at 12V both copies 12h, and now they are really very bearable because besides noiseless. Everything from 1000 rpm is slightly audible above 1200 rpm they are clearly audible. But what fan is not from these revolutions? Once any obstacles are the intake of these fans, they begin to whine, because I would no longer recommend. Sit against blowing on a radiator, this disturbs not technically sound. Therefore, I can the NF-A14 PWM only push configurations where the fans can "breathe", recommended for this purpose, however, I know no better.