I have the same hardware as originalplaid, except I have a lot more RAM, and P7 is so much faster than P6 on it that it's hard to believe, notably renders, which are 5+ times faster. Judging from the comments I've seen posted here about P7 for Windows, you should go with P7 for Mac if you want to avoid many of the crashes and freezes that even high-end Windows machines seem to experience with it. P7 on my Macs has been rock solid, stable and extremely fast. P6 was not universal binary and had to run in Rosetta, so that's NOT any kind of representation at all of how P7 will run on originalplaid's hardware. It's any easy choice -- go with P7 for Mac. S