http://www.hexus.net/content/reviews...lld19JRD0xMzM3DDR stands for Dual Data Rate and is the replacement for SDRAM. The best analogy we have come across for how DDR works is: If the memory is visualised as a bicycle pump, SDRAM “pumps” push data into the “tyre” each time the barrel of the pump is pressed down, whereas DDR pushes data both on the downstroke and the upstroke of the barrel so filling the “tyre” at twice the speed.