If you want to cut a segment from a larger clip, suppose you only need a few seconds from a 2GB file. Select that region and render it to a new track.
If you have some complex compositions of F/X and transitions that you’re finished with, then render hat section to the new track to reduce the load on the processor.
Before we got Track Grouping, I would often render sections of my projects to a new track just to reduce the number of tracks. (It is not unusual for me to have 40-50 tracks in a “simple” project.).
Steve Mann
MannMade Digital Video
http://www.mmdv.com