The AMD760MP Chipset
First, I have to note that the 760MP is not a complete new chipset. Only the AMD762 north bridge, which communicates with the two processors, the system memory and the AGP, is of new design. The AMD766 south bridge that completes the 760MP chipset is already known from the previous AMD760 chipset. This south bridge is of classical design, connecting to AMD762 via the PCI-bus and providing the common features as ATA100 interface, 4 USB ports, interfaces for the serial/parallel ports and the SM-bus controller. The AMD762 north bridge is the interesting and obviously important part of 760MP, as it hosts the two AthlonMP processors that run in SMP configuration.
The AMD762 provides two EV6 buses, one to each AthlonMP, and a DDR-only memory controller that runs the memory at the same clock as the processor bus, either 100 MHz (200 MHZ DDR) or 133 MHz (266 MHz DDR). 762 does not support any PC100 or PC133 SDRAM, just as its older brother the AMD760 chipset. Tyan's K7 Thunder motherboard, which is currently the only platform with AMD760MP that is available on the market, requires registered DDR-DIMMs. This DIMM type comes with additional buffers to reduce the load of the memory controller. The K7 Thunder does not run with the common unbuffered DDR-DIMMs, although the AMD760MP specifications allow the support of up to two of them. In a few weeks or months, we will see low-end AMD760MP motherboards that will probably support two of the common unbuffered DIMMs as well. AMD762 supports the typical ECC goodies, including 'memory scrubbing' as you would expect from a workstation/server chipset. The final feature that 762 has over the single-Athlon 761 north bridge of AMD760 is the support of 64 bit PCI or short PCI64. While PCI64 is rather uninteresting for desktop as well as most workstation users, it can be of importance for servers to accommodate cards with high I/O loads.
