The problem for me was latency (from another G5), as I posted in another thread. It was about 150ms - totally unusable. That was when it wasn't playing, so I'm confused why you'd have such better results.
You might try running a TOSlink cable from your main machine to the slave for sync (you have to go to Audio MIDI Setup and tell the computer to to do that). That might affect the change in latency - assuming you don't have PDC turned on and that's all it is.
You might try running a TOSlink cable from your main machine to the slave for sync (you have to go to Audio MIDI Setup and tell the computer to to do that). That might affect the change in latency - assuming you don't have PDC turned on and that's all it is.