I've noticed that AMD has generally preferred the more conservative route. While Intel goes for brute force architectures that enable higher clock speed, ie P4 / RDRAM, AMD has gone for more intelligent, yet evolutionary designs.
All things being equal, increasing performance through higher clock speeds will generate instability more often than increasing performnce by making a more intelligent chip, which is what AMD has done. While DDR and QDR, if and when it arrives, will always be able to trace its roots back to SDRAM, RDRAM is more revolutionary. But its key negative, that it does so little per clock cycle, bugs me. That plus the fact that its been years since its introduction, and its prices are still double that of DDR.
Intel has seen it, and its no coincidence that they immediately surfaced with i845DDR immediately after their contract with rambust expired.
I hope the bastards at rambust are forced to pay back every penny they conned out of the Jedec organizations.