I chose because AMD doesn't support it because I never plan to go Intel again. Also, AMD will probably never use DDR2, and skip to either DDR3 or XDR. Ask (cf)Eclipse what these are, I'm a little fuzzy on RAM in general.
pure latency. i can go from seeing 2-2-2-5 to 3-3-2 no matter what it is. xdr, all i can say about xdr is rambus, eww! ddr3 will probably be the ram of choice, as it can hit high speeds, ddr1200+ , the only issue is the price.