There's a thread on Apple's Discussion Boards this week regarding trouble with the latest MacBook Pros with 7200RPM drives. Specifically, the machines are clicking (most users report the click as coming from the drive's location) followed by a beep that's, as far as anyone can tell, not coming from the speaker, as demonstrated above. It's quiet in the video, so crank up the volume and listen closely. Finally, its occurrence is unpredictable.
No clear answer has been reached yet, but Other World Computing (OWC) shared some relevant information with MacNN:
"The issue may be with Seagate's Momentus 7200.4 G-Force hard drives ... Affected units are said to spin up and down frequently, which may be generating the sounds reported by users ... The G-Force technology is said to be mostly irrelevant on Macs in the first place, as a result of pre-existing anti-shock protection."No one at the TUAW offices has one of these machines, so we haven't experienced the problem. If you have, let us know in the comments and we'll see what we can dig up. Thanks, and good luck.