Edit: Everyone seems to agree that 3rd party RAM does not violate the warranty, despite what the Apple Store staff and the Apple sales person on the phone said to me. Thanks, everyone! Sorry I can't edit the subject heading. --------------- So I just bought a MacBook at the Apple Store in Manhattan. I was told by the floor sales person that installing my own RAM would void the warranty, but that I could bring the computer back in and have the RAM installed for free. It turns out though that Apple's deal for upping the RAM to 1GB is not bad ($100 for two 512 sticks, though they keep the two old 256 sticks), so I called to ask if I could bring it in to add the RAM. After a lot of backing-and-forthing, they all agreed: 1) any RAM you install yourself voids the warranty 2) they won't install third-party RAM 3) if you buy RAM from Apple after the purchase, it costs $200 to upgrade to 1 GB (though you get to keep the old sticks)--plus $30 more for installation if it's after the first 14 days. I'm still not 100% certain this is all true, but the guy consulted a lot of people when answering these questions. I thought I should post this to warn folks to get the RAM when they purchase, or else they lose either $100 or their warranty. (Though I suppose you can get some of that $100 back by reselling the two 256 sticks.) As for the 2GB option, I guess you have to pay Apple's high prices or lose your warranty. Luckily, I hadn't opened the box yet, so I can return and rebuy it with no restocking fee (which otherwise would be 10%, or at least $110).