n0nsensical

There are a few reasons for AMD systems to not be using DDR2. First, AMD CPUs have their memory controllers on the chip while in Intel systems they are external to the CPU. This means AMD would have to make an entirely new line of CPUs to support DDR2 that wouldn't be backward compatible with any existing motherboards or RAM.

Second, at the moment, DDR2 does have higher bandwidth than DDR, but generally higher latency as well. Some applications are bound by bandwidth and some by latency, so it's not a clear advantage all the time to be using DDR2, not to mention the fact that DDR2 is more expensive. (Also, might I add, high-performance DDR can be clocked high enough to hold its own against DDR2 in the bandwidth department as well.)

These are also major reasons why AMD systems more or less dominate Intel systems in games, because games are generally latency-bound rather than bandwidth-bound (coincidentally, lower network latency is also more important than bandwidth for online games). The combination of low-latency RAM and the on-chip controllers means AMD systems are much better suited to those type of applications, but less suited to things like video encoding that require high bandwidth.

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