[Bleuachdu]

I just got my new PC equipped with 256mb of RD1066. I've always been a DDR user and I'm not sure what to do here. I want to get up to at least 512mb. I have 2 slots free on the mobo, meaning I have 2 128mb modules on there now. I know that I have to install the DIMM's in pairs as its a dual channel board. The question is, do I have to install two more 128mb modules or can I up the anti a bit and buy 2 256mb modules, giving me a total of 768mb? I'd really prefer the latter, but if I can't have 2 conflicting "sizes" of memory on the board then I'm SOL. Thanks guys, I'm sure someone can help.