Sorry for this cross posting, but I have all of these: G4 Tower, iMac and iBook. I Installed 10.4 on the G5 iMac first, it went flawlessly and not one problem. The G4 Tower is a dual 1 gig Quicksilver and it took a total of 3 attempts at installation before it finally worked. The iBook installed just like the iMac. The iBook is a G4 1.2 gig 12 incher. Thought I would let everybody know my experience. Tim