And it says the maximum memory you can install is 512mb....So the max memory you can install is 512mb of PC133 ram...PC133 is the specific speed of RAM you need and now you know your limit is 512mb so now it's up to you how you want to go about upgrading it. My suggestion is simply 2x256, however upon checking zipzoomfly.com right now I see they don't offer any 512mb kits of PC133 so you might either have to buy two seperate sticks of 256mb for around $60 a piece or one 512mb stick which is about $94 seen here: