Streamers and punches exist in a separate sprite track, and DP5 relies on QuickTime to do a good job of compositing the sprites on top of the other video track(s) in the movie file. QuickTime certainly has to work harder when it is playing back sprites and other video at the same time, which is why CPU usage goes up during portions of the movie that have both sprites and regular video. It is no different when you bounce to a QuickTime movie, because the finished QuickTime movie contains the same sprite track; therefore, QuickTime Player or any other QuickTime app is going to get similar playback performance.

If you want the best possible playback performance, you can do this:

1) Bounce final work to a new QuickTime file, including the film events sprite track.

2) Use QuickTime Player to convert the movie to one DV track (combining the exisiting video and the sprite track into one new DV track). You do that using File menu> Export, and choose "Movie to QuickTime Movie".

The resulting movie will put less of a burden on QuickTime during playback, since everything is in one format in one video track. It will also play out the FireWire port. However, once you have done this, the film events are married to the video and cannot be removed or edited from this copy of the movie.