Snappier navigation

I'm writing on behalf of someone with a large audio collection (28000
files, 120 GB). This person is happy with Rhythmbox, except that it's
pretty slow.

I don't have exact measurements, but it's something in the order of:

* 3 minutes for startup
* 30 seconds to switch to a song from another playlist

The user considers playlist switching as more important than startup
time. The hardware is a modest laptop.

The only thing so far I could think of to speed things up is to mount
the data partition with noatime. That seems to have marginally improved it.

Are there any other settings I could change to make it snappier? Or
plugins that could help (I didn't spot anything relevant in the list on
the wiki)?

I was thinking it could be helpful if Rhythmbox could manage multiple
collections. This person has many files that are used rarely, so those
could be put in a separate collection (e.g. a USB drive). If that
collection could be actived/deactivated on demand, then Rhythmbox would
only have to deal with the often used collection most of the time.

I appreciate any tips on this subject.