I guess this has been discussed before but it was news to me. It might be of some use to those who have one of the pre-unibody Macbook Pros, i.e. the early 2008 Macbook Pro. The official RAM limit is 4GB (so 2GB x 2 sticks.) Apparently you can throw 6GB in there are encounter no problems even under heavy load. So, a 4GB stick + 2GB stick. All in the information you need is here: http://macperformanceguide.com/Mac-OWC6GB.html http://eshop.macsales.com/shop/memory/MacBook/Pro/Core2/ Available from OWC. I already have 4GB so all I need is a 4GB module to use with the 2GB already in there. I've got one on order now. If you've got 2GB (1GB x 2 sticks) then the 6GB upgrade is available as a package, I believe. Cheers.