Okay, this is a weird one, which I've noticed only because the fan on an SP3 that I bought and returned failed and so I check my current unit every now and then for the same issue. Here's what it is: a clicking sound that I can hear where the fan exhausts on the upper-right hand quarter of the machine, but only when the SP3 is sleeping. I'm not terribly concerned about it, except it seems to imply that there's some sort of electrical activity going on when you'd think there wouldn't be. I have no idea what might cause it, and I even have a hard time describing it--although, it ALMOST sounds like the fan is running at a very slow clip, because when you turn the machine back off you can hear the clicking sound seem to ramp up. Except not, because maybe the sounds are just melding together. Crazy, I know, and mostly of passing interest. Anybody else have it?