My 2006 Mac Pro now has a subtle oscillation sound. Before it was totally constant, just a whisper "whrrrrrrrrrrrrrrrr". I use SMCfancontrol for it, but have the fans set to the default (lowest) setting. This morning when I updated to 10.5.2, the fans are still quiet, but there is a DEFINITE oscillation, its like" Whrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr" I've tried using SMCfancontrol to change the speeds to try and balance it out, but it's like it's got some sort of oscillation or resonance in the case. And it is absolutley a new sound since 10.5.2. Anyone else with an 2006 MP notice any changes?