I have been running Pro Tools 9 HD on a macbook pro with Digi 003 rack+ in live performance for a men's quartet for about six months (Pro Tools 8 prior to 9 release) without any problems. With live mic ins, recorded channels, affects, and aux sends, we typically have upwards of 20 active channels with a variety of plugs on most. Macbook pro is 2.6ghz core 2 duo with 4gb ram.