Only have 256MB of DDR RAM, looking to upgrade to 512MB. Unfortuantly I'm unsure what type of DDR RAM I should buy. Will be buying from Special Reserve - http://ukram.com/ How do I work out which type of 256MB DDR RAM to buy? When I phoned SR, the guy wasn't sure but suggested the '3200' RAM. PC was bought in the last year or 2, and is a P4 2.66Ghz Pesario from Compaq.