DDR2. I'm not 100% positive about the PCIe slot, but I think it's a gen 1. That board has a 945 chipset, and I don't think the gen two slots came out until the 965/P35 chipset. 915-945/955 were gen one, the old 8xx boards were AGP, and the 965 and up were Gen 2. That's how I remember things anyways.