Just upgraded my CoreDuo (_not_ Core2Duo) MacBook to 2gig of RAM. Woah! What a difference it makes! No more spinning beachball! Switching between apps & opening large mail folders is now noticeably quicker. If you're thinking about more RAM, here's a suggestion to quit procrastinating & buy more now. I paid about £55 including tax for the 2 x 1gig sticks from Crucial, far less (I'm sure) than it was a year ago when I bought the lappy. Looking at Activity Monitor now I can see iChat, iTerm, 3 Mail windows & 10 tabs open in Safari with about 700meg of memory free, but during a 2 or 3 hour session earlier I was running consistently around the 1gig mark, so that might seem to be the sweet spot for OS X running on this processor. Stroller.