I have noticed that .cpr files are requiring a much longer time to save, even with just midi-only files. I was able to cut down on the save time considerably by removing an unused Halion Sonic SE instrument that was not being used.
The issue began when I was importing midi data into a frest .cpr song. Each time a new midi song file was imported it created a new Instrument instance of Halion Sonic SE. Since I needed less than 16 instruments I simply assigned all the outputs to one Halion Instrument. Then deleted the other. I compared save times by counting how many rotations the Wait Circle made in W7 while saving. It went down from 5 to 1 rotation. Quite a diff. The file size halfed as well.
Hope this helps some of you too.