Hi Eric, I was thinking of upgrading my Macbook Pro 2.33Ghz 17-inch to 3GB as well. Can you offer any experience of how this speeds up or affects performance? A vendor's site reported that if using different densities (1, 2Gb) of ram, this would be sub-optimum and the machine prefers pairs of same amount. Does that mean to get best performance you need 2x2GB cartridges anyway? bit confused! J