Apple’s Knowledge Base says: PowerBook G4 (Double-Layer SD) audio stutters or skips. When playing music in iTunes, it tends to skip. Out of the blue, like a stuck CD. Its highly annoying, and I never noticed this before on previous Macs.
Adam Curry (podcaster extraordinaire) poked at the issue by mentioning it repeatedly on The Daily Sourcecode, and Apple finally came up with an interesting solution: “To avoid this, run only one audio application at a time.”
What the heck?!? Rebooting the same Powerbook into Fedora, and playing music in both Rhythmbox or XMMS doesn’t exhibit this “skipping” aura. Both with MP3s or OGGs.