[NeXTLoop]

I'm stumped by this one. I have a Quad-Core i7 15" MBP with 8GB of RAM. It has a 750GB Western Digital Scorpio HD running at 5400RPM.

Whenever I play a song that has a moderate to aggressive beat and base, the song starts stuttering. It will just pause for about half a second numerous times throughout the song. This happens regardless of whether I play the song in iTunes or Quicktime, and happens with any song that meets the criteria. While the computer is struggling with the song, the machine's overall performance completely tanks. Spinning beach balls left and right. If I lower the volume to half, or lower, the problem goes away. My buddy has this machine, but with an SSD drive. His has no problem with any kind of music.

My theory is that the volume causes enough vibration in the unibody frame to trip the Sudden Motion Sensor, causing the HD to park its head for a split second. Does that sound likely? Any other ideas?

[P]

Certainly possible. Does it happen when you play with headphones as well?

If the sound makes the SMS trigger, I think your HD may not be fixed correctly.

[jmiddel]

If P is right, every time you experience a stutter your HD is briefly loosing physical connection to the computer, which will eventually cause corruption and data loss. Open the thing up and make sure it is seated properly, ie snug. If it is well seated, it might be a HD problem, I've had WD drives progressively die doing similar weird stuff. I'd back up up up After all, these computers are routinely used to play music, and I think Apple's engineers know just how loud some people will play stuff