I know the new cat is 64bit but about next to zero after that. But I noticed this: I installed a widget that kept an eye on my 2 gigs of ram in my ALiMac 2.8. Over the past few weeks that it was installed I noticed my "free memory" hovering between 700 and 200 at the low end. I just installed the system widget and it reports free memory at 1421. Now that is some kind of a change. Got to love this new cat.