Is it practical using a 128GB SSD in a Mac Pro? I was thinking about getting the Crucial M4 128GB, and using it mainly for the OS and other files I use frequently, and keeping things like photos/videos/other documents etc on a separate 500GB disk - so basically half of my home folder would be on the SSD and half on the 500GB disk. How would I go about setting that up? Am I just asking for trouble? Also, would my time machine disk (a 3rd 640GB drive) back up both my SSD and the 500GB drive? (Again how would I set that up?) Thanks for any help!