There was also some documented cases where the CPU would emit some sort of whine on the earlier MacBook Pros. Is the sound coming from under either speaker? I've had both fans in my MacBook Pro replaced since I bought it 1.5 years ago. If the sound comes from under the trackpad it might very well be the HD. Since it happens under high CPU load, I would lean toward the fans, based on my own experience.
10/11/07 at 9:52am