Music now takes a long time to start playing

I use my Boxee Box to access music on SMB shares, mostly using m3u playlists. In the past, when I selected a playlist or individual file, it would start playing almost immediately. Lately it takes a long time to start playing when I select a track or playlist. The length of time seems generally related to the number of tracks in the playlist or folder I'm starting from.

Most of my playlists include thousands of tracks. When I select a playlist, the first track doesn't play for a very long time. I started one and walked away, then forgot about it until it started playing over twenty minutes later. Smaller playlists might take 5-10 minutes to start. Once the first track plays, the rest play fine, with no gap between tracks.

If I browse to a folder containing one album (10-15 tracks), it takes seven to ten seconds to start playing.

I made a test folder of 500 tracks and shared it from my Windows Home Server and also from a Windows 7 Pro machine. I then created playlists for each location. When I select a track in either share, or select that share's playlist, it takes anywhere from one to two minutes before the track starts playing. It doesn't seem to matter much whether I play from the WHS or 7 share, or whether I play from a playlist or from the folder itself. (The times vary somewhat even when playing from the same source/method, but they're always in that range for the 500-track playlist.)

Attached debug log is from playing the 500-track test folder on Windows Home Server. Playback took about 1 minute, 20 seconds to begin.