I have a 15-inch 1.5 GHz Aluminum PowerBook G4 with 512 MB of SDRAM. My question is; sometimes I like to have 5+ applications open at the same time. Is it worth it to buy an additional 512 of RAM? How much will it speed things up? Also, I need to send my Powerbook in to Apple to get something repaired. Will they install an additional 512 of RAM or do I have to buy and do that separately? I know Apple RAM isn’t cheap, but I’d like to keep it under my Applecare warranty.