Chapter 1: Introduction
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1-2 Chipset Overview The H8QM3-2/H8QMi-2 serverboard is based on the nVidia MCP55 Pro and IO55
chipset. The MCP55 Pro functions as Media and Communications Processor (MCP)
and the IO55 as a PCI-E Tunnel. An NEC uPD720404 chip is also included as a
bridge for the GB LAN ports and the PCI-X slot. Note that the controllers for the
system memory are integrated directly into the AMD CPUs.
MCP55 Pro Media and Communications Processor
The MCP55 Pro is a single-chip, high-performance HyperTransport peripheral con-
troller. It includes a 28-lane PCI Express interface, an AMD Opteron 16-bit Hyper
Transport interface link, a six-port (3 Gb/s) Serial ATA interface, an ATA133 bus
master interface and a USB 2.0 interface. This hub connects directly to CPU1.
IO55
This hub connects directly to CPU2 via a 16 x 16 1 GHz Hyper Transport link. The
IO55 includes an interface for the PCI-Express slots.
NEC uPD720404
This I/O bridge chip provides one PCI-Express x4 upstream port and two PCI-X
domains. Each bridge supports PCI masters that include clock, request and grant
signals. This hub links the MCP55 with the PCI-X slot (slot #1) and the Gb LAN
ports.
HyperTransport Technology
HyperTransport technology is a high-speed, low latency point to point link that was
designed to increase the communication speed by a factor of up to 48x between
integrated circuits. This is done partly by reducing the number of buses in the
chipset to reduce bottlenecks and by enabling a more effi cient use of memory in
multi-processor systems. The end result is a signifi cant increase in bandwidth
within the chipset.