As I said earlier in the week, I’m loving my MacBook. Fairly early on, however, I noticed a recurring sound that sounded almost like the computer was moaning rhythmically. Naturally, my first thought was that I had somehow received a zombie MacBook, which was crying out for delicious brains.
It appears I was mistaken. But only by a couple of letters; MacBooks are not, in fact, moaning, but rather mooing. And one intrepid MacBook owner decided to vivisect his MacBook to determine what was causing this strange noise (my guess, an entrapped dogcow, was sadly not to be). In fact, as you might guess, the “mooing” was being caused by the MacBook’s fans ramping up as the processor temperature increased.
I’m glad to have the source of the trouble identified; I was a little worried that I was the only one experiencing this issue. In truth, it’s not a very distracting sound unless you’re working in utter quiet, and even then it only comes on sometimes. Still, I’m relieved to know that my machine isn’t zombie-infested.
[via Gizmodo; picture from Penny Arcade]
Some have reported that plastic films are covering the vent where the LCD hing is. This may be related to your "mooing" sound from the fans.
I bought my macbook a week ago and mine is absolutely silent. It seems that not all MacBooks are affected by this.