Another cool feature of REAPER I only just heard about. You can set up a second (or more!) computer running reamote.exe (it’s part of the application) and it will share your plugins’ CPU / memory requirements! How cool is that?!?!
I tried it yesterday. Even though my plugin usage was quite low (12% for four tracks with some eq, compression, reverb) I had a second computer do the reverb for me and my CPU usage went down to under 3%… very very impressive.
Go to http://wiki.cockos.com/wiki/index.php/ReaMote for more details on setting it up and whatnot.