I have a 2.4 SR MBP with 4 gigs ram and an external firewire 800 drive for media. I notice that when I use AE CS3 on it, the preview renders are very slow, and the ram previews are also slow. I have tried all of the performance enhancements suggested in the help files for AE. I get faster ram previews using my old PC with a Pentium 4 3.2ghz and 2 gig ram when using AE CS2. Is there something that I am doing wrong, or is AE CS3 just too much for a MBP and requires a mac pro with multi core xeons? Thanks for any advice.