When I used to put my Dell on standby, it would shut everything down, the rear exhaust fan, the psu fan, all that. It was silent. But then I moved to a new apartment, and when I put my dell on standby, the fans didn't shut down anymore. But, since it only had a weak psu fan and a weak exhaust fan it didn't really matter. Now that I have a computer with 2 chassis fans, 2 psu fans and a cpu fan, its much more noticable.