For the uninitiated, the K8 platform uses high-speed, unidirectional HyperTransport links in place of traditional parallel communcation, and the K8 chips incorporate their own DDR memory controllers. Internal communcation is more like a network than a traditional PC, so instead of a north bridge, you get an AGP sitting on the other end of a HyperTransport link. Data is sent to the AGP chip using a "tunnel"a VPN, more or less. AMD showed off an AGP 8X graphics card (SiS Xabre) running on an AMD Graphics Tunnel chip in AGP 8X mode here today.
If it all works right and well, the K8 should be extremely fast, especially in multiprocessor configs. Once it arrives.