I've managed to create a patch which actually maxes out a quad core 3 GHz Mac. D'oh. I tried to use the non real time driver, but got very odd results. The patch uses pattr to go through a number of presets. What happened when I attempted nonrealtime was that a 38 minute piece was compressed to 7 seconds! What's going on?!
Secondly, using pattr vastly increases the CPU load. The sound-making parts of the patch typically run at about 25 - 40% CPU, but when I start running the automation (and the patch begins interpolating between presets) the load gradually climbs until eventually playback starts to stutter at around 70%. Is there any way I can reduce the impact of interpolating between presets?