As for being maxed out, there is a lot of music on the external HDD but it plays perfectly from iTunes and only stops, jumps, freezes or shuts down when played through the SB.
In troubleshooting, one test you iTunes users might try to narrow things down if possible, is to determine how well these tracks play on another computer in your network accessing the tracks through iTunes DAAP sharing. This is what the SoundBridge is really trying to do.
Sometimes these sorts of problems can be related to the tracks themselves (although probably not if they stop in the middle)....new FAQ post on .aac files here:
But available CPU/memory on the computer used as a server most certainly has an impact on Soundbridge's performance. For example, if my kids are playing graphics intensive games on my Windows XP box, I'm pretty much limited to internet radio on my SoundBridge until they stop.