I have had issues with my right fan making noise for a few years. I believe the bearing has been degrading for a while. It has gotten progressively louder but I have been monitoring my fan speeds and CPU temp via the iStat Pro widget. All of a sudden it went completely quiet, but the RPM says it's still up at 2000. How is that possible if all of a sudden it became quiet? Is the iStat Pro reading accurate? I figure that the bearing bound up or something and that my comp may occasionally overheat and shut down. It is starting to make a little noise again but nothing near how loud it was for a while (think an airplane taking off). A replacement is on order and I will switch it out, but anyone have an idea of why it might have gotten quiet all of a sudden but still apparently function??
