Right now I have a P5N-D with an e8400 (3.0ghz), 2gigs of DDR2 800 RAM, and just bought a gtx460.
I want to get win7 64bit and 4 more gigs of RAM for a total of 6gigs of RAM. I also want to buy a second gtx460 to SLI it, but when I was seating my current one I realized that a second card would be practically rubbing against the first, because there isn't much space between the two slots. I might have to buy a new mobo if the two cards start overheating because of how close they are, and if I do that I wanted to know if it would be a good idea to use ageing DDR2 RAM on a mobo that can use DDR3 RAM instead. Would it be a waste to buy more DDR2 RAM now if I might be buying a new mobo later?
It would not be a good idea to buy more DDR2 because it's outdated and would be a total waste if your planning on a new motherboard upgrade, you can't use DDR2 in a DDR3 MB the slots are different and the sticks won't fit. So that makes buying DDR2 a waste unless you can sell it on ebay later or something.
How long before you were thinking of doing the MB upgrade? If you do end up buying more DDR2 then you want to make sure that your getting the right combination of sizes, your thinking of adding another 4gb and you should consult the MB users manual to make sure your getting the right combination.