Yea AMD still uses a FSB of 200mhz, HT or HyperTransport doesnt have any thing to do with the FSB, is a bridge connect and on his 4800 it should be set at X5, if hes seeing 800 then its set at X4
HyperTransport is primarily a chip-to-chip interconnect, so an important element of its design is its bridge capabilities to board-level bus systems, such as AGP, PCI, PCI-X and PCI Express. That's required for providing a HyperTransport-based system board with access to the huge array of I/O devices, ranging from AGP desktop graphics cards to Ethernet, Fibre Channel and SCSI adapters.
Each HyperTransport link consists of a host device and an endpoint; any of those devices may be a bridge to one of those slower board-to-board networks. The original HyperTransport specification defined the PCI and AGP bridges. HyperTransport 1.05 created a bridge to PCI-X; HyperTransport 2.0, which appeared in 2004, added in the PCI Express mappings and appropriate bridge technology.