My box is dated, and I'm piecing together a new system. I plan on going with a new AMD64 X2, depending on prices I'll probably go with the 3800. I love Asus, so I want to stick with one of their boards, I would love SLI, but I'm going with a single card for now (money constrants) but would like the option to slap in a second card in the future. I'm stuck and confused on memory. DDR2 vs DDR, whats the difference. How do I know which motherboard will support which? Is a different DIMM connector, or is it all the same? If I don't plan on OCing, do I even need DDR2? But I really don't want to upgrade my motherboard in a few months just because my ram is dated. Is DDR2 even an option with an Nforce chip? Basically what should I be looking for when making a ram purchase? I'm planning on starting out with this motherboard: http://usa.asus.com/products/mb/socket939/a8nsli-p/overview.htm Thanks in advance. I'm just drawing a blank on memory at the moment. Also, side question, I'm using SATA seagates at the moment, that are only SATA1, are the faster SATA (3Gb/s) backwards compatable?