Hey folks. I have a MacBook6,1 (previous generation) and I'm thinking about upgrading the RAM (again) from 2x2GB to 1x2+1x4 (6GB) or 2x4GB (8GB). I've read a lot about people experiencing issues with a 8GB configuration being unstable in these machines, and Apple themselves say that you shouldn't go past 4. I was wondering if anyone has experience with this specific machine in either 6GB or 8GB configuration. Thanks! PS: When it comes to the Genius Bar, what should I do if I have 6/8GB in this machine? Downgrade before going in? I never get rid of old RAM - I keep it around on a huge shelf mostly full of PC-66.