Are you under the impression that every time you make a change to the playlists in PMM, that PMM will then recopy ALL of your music to the DMS?
This isn't the case. PMM will only update those files that have changed, or have been added or deleted.
Point PMM to your PCs music folder. Create your playlists in PMM. Add the playlists to your DMS. Then save/eject your DMS. Come back when it's done.
From then on whenever you add or change a playlist in PMM (and your DMS), only that CD has to be copied over to the DMS, so the process will be much quicker.
Here are some thing you can do to lessen the impact of copying songs to the DMS:
1. Get a USB 2.0 cradle.
2. Remove the drive from the DMS and hook it directly to your computers IDE bus with a 2.5" to 3.5" IDE adapter.
3. Drink less coffee.