I am very surprised that you would experience problems with a G4 with that much RAM. The system periodically freezes on you? Does it happen past startup? There is a reason it could freeze for awhile right at the beginning (namely that dns lookups as it's trying to resolve the router.limewire.com address can freeze the Mac if they take a little while -- ignore this if it means nothing to you), but freezes once you're connected to the network are very strange. Do you ever get freezes, for example, after being connected for 5 minutes or so.

Also, if you have a chance it would be great if you could take a look at the Connections tab as soon as possible on startup to see if the freezes seem to be related to who it's connecting to. You could see it freeze, for example, when it's connecting to router.limewire.com or connect1.gnutellanet.com, and then unfreeze right when these disappear.

Thanks.