Very slow sync

I've been experiencing very slow sync times (2.5 min) since iTunes 9.0.3. I thought that it might be a bug in that version which would be resolved in 9.1, but the issue persists. I only ever sync Apps, the rest of the categories I manage manually, yet hitting the Sync button still results in iTunes hanging for 2.5 min whilst displaying the "Syncing iPod..." message. So far I've tried restoring my iPod, reinstalling iTunes and running diagnostics, which showed everything was working fine. Does anyone have any other suggestions?

Thanks.