Good article, but one thing: In AMD's Dual Core implementation the cores are NOT linked together using HyperTransport. They uses a more direct coupling called SRQ (System Request Queue). The advantage is that cache coherencey updates between the cores are much faster. I.e. AMD's dual core implementation is no different to it's single core cousin with respect to HyperTransport/crossbar/memory-controller. Of course Hypertransport-Links can be used to extend the system with further CPUs, but that is a differnent story.