Matthew Parrott, the "noticeable better performance" only applies to bigger hard drives and not any of the audio or video capabilities. It will allow for a better access of those drives, this will be noticeable on playing playlists. etc. The ram is part of the logic boards and not necessarily which generation it is. Anyhow, here is what I got:
820-1763-A motherboard can have 32MB RAM or 64MB RAM. The 30GB 5G iPod uses the 820-1763 board with 32MB RAM while the the 60GB 5G iPOd uses the 820-1763 motherboard with 64MB RAM.
The 5.5G iPods use the 820-1975-A motherboards. The 30GB 5.5G iPod uses a 820-1975 board with 32MB RAM. The 80GB iPod uses a 820-1975 board with 64MB RAM.
Hope this helps, good luck.