Hey, guys. I notice when I run OS X, my Mini 9 hums (emits a high range frequency) when I run OS X. The sound is coming from the left side of the key of the Mini 9 normally when it is not under load. When I run Win 7 or Ubuntu 9.04, I do not hear or notice the sound, but the system sounds like it is under load more often, especially in Win 7.
I started noticed the noise for the first time last night. The Mini 9 still runs perfect as far as I can tell.
Anyone else notice this noise while running OS X?