Question for iTunes users.

Various operations in iTunes 4.9 have gotten very slow since I added all my music directories to my library. These operations include getting info on a track, paging to the next screenful of tracks displayed in the library, and searching through track metadata. For these operations, I get the "spinning beachball of death" for a bit, but fortunately program control has always returned.

Is this a problem that can be solved by upgrading to a newer version? I heard there were some issues with iTunes 6.0, so I've waited. Or is this a problem best solved by using something other than iTunes? If so, what other software would you suggest?

(The system is a 15" PowerBook G4 running Mac OS 10.4.4 with 2GB of RAM. The directories are spread across three drives, one internal and two external, one connected using FireWire 400 and the other using USB 2.0, for a total of slightly over 600GB of files. It doesn't seem to matter if I switch the drive connected using FireWire to one of the USB ports.)

Thanks for any useful suggestions!