I have a G3 900mhz iBook with 640mb of RAM using an external audio drive and have had no issues with editing 32 tracks. I use this setup for mobile recordings and editing away from home. You do have to watch your plug ins, but that is the case with any system. As far as using PT without the Mbox, it is not possible. The Mbox does not require power, but PT does reccomend to not run on battery power.