How many instrument tracks with plugins does anyone get before having problems? After 3 I get playback hiccups and the the occasional "Lost communication with hardware device." I'm using an iMac 20", 2.2 GHz Intel, 4 GB RAM, 750 GB internal HD, 500 GB external FW 800 external HD for audio files. I've tried all sorts of settings changes with little success. I just upgraded to Pro Tools 8 LE, but it's the same as version 7.4.
Maybe the workflow should be to record a MIDI performance, bounce to audio track, then repeat. Awkward, that.