I posted this issue in the iTunes forum but thought I"d try here to, since it's probably more of a G4 issue than iTunes! I recently upgraded this Sawtooth's processor from a dual 500MHz to an OWC mercury 1.2GHz (single). I expected to play movies better since the minimum requirement for iTunes movies is a 1GHz or better G4. The movies do play better since the upgrade, but they still stutter on playback. Really not watchable. I can play mpeg movies fine with the VLC player, however. It's just iTunes movies that stutter.
I shouldn't need a faster processor than the 1.2GHz with its 2mb L3 cache! Do you think upgrading the video card from the current ATI Radeon 9200 PCI to the Radeon 9800 would help?
PowerMac G4 (AGP), Mac OS X (10.4.11), Sawtooth, OWC 1.2GHz, 768mb ram, Radeon 9200 PCI