I'm currently limited to 2 gig or DDR3 period (only have 2 DDR3 slots) but I can go back to DDR2 if need be, the board also has 4 DDR2 slots, so at least I have the option if I need more. I would be nice if they made 4 gig sets of DDR3, but even if they did, I'm sure that I couldn't afford it.