If I recall correctly, it's supposed to prefetch data 2x as much as regular DDR, and on top of double data rate it would make theoretically 4x as fast as regular SDR memory. Now, I don't know exactly what prefetch is, I'm just telling you what I've read. And also it's designed to consume much less power than regular DDR modules. And since they are going to use even smaller chips (0.11 micron I believe) it's supposed to be able to be pushed to higher frequencies.