Specifically the hard drive fan runs at 1600rpm and the optical fan always runs at 1350 rpms. Those fans run faster than my 2007 24" 2.4ghz iMac. Somehow I figured with the cooler running ddr3, 9400M igpu and better cpu architecture that this new 2009 20" iMac would be dead silent because the fans would barely have to run. Or at least be less noisey. But that's not the case. Anyone have any fan speeds to report on new iMacs? Particularly the 20" model? Download the iStat Pro widget and report your fan speeds today!