I'm not really sure about the minimum needs for 480 playback. You could probably get the best playback using VLC 1.1.12. My 1Ghz G4 iMac can barely playback the Apple TV 1G preset in Handbreak without stuttering. Haven't tried it on my 1.25Ghz one. I do know that my 1.5Ghz Cube can playback the Apple TV 2 Handbreak preset in VLC 1.1.12 without a problem.