I recently upgraded a friends iBook G4 to OS X 10.5, and installed the latest iTunes, all so she could use her new Nano. Since doing this, when playing music in iTunes or YouTube there is popping and stuttering in the audio, though video is playing smoothly. Music on Pandora, on the other hand, plays perfectly. I've tried changing various settings in iTunes and Quicktime, and have also tried installing a different music player (VLC) but we're having the same issues. For reference, the iBook is the 12" model, with a 1.33GHz processor and 768MB of RAM. The OS install was clean, to a brand new hard drive. Everything else works perfectly. Any ideas or suggestions would be greatly appreciated!