Digital Performer has a setup like this too and I imagine that the Sonar stuff would work in a similar way ... DP does "predictive cacheing" ... in other words as you play each track the first time though it writes it to a temp file fully pre-processed and until you make any changes on that track it uses that cached file. Saves a TON of CPU and other resources as it also does that on-the-fly with all your plugins, so until you open the plugin to make changes it doesn't use any CPU again. With DP it's all built-in though and runs behind the scenes (you don't have any choices to make and you don't have to actually freeze/bounce a track to get the benefit).
