Overview
   The Intel® 840 chipset is a high-bandwidth chipset designed for workstation and server platforms based on Intel Pentium II processor / Intel Pentium III processor architectures. The chipset contains two main components and additional optional components that provide expansion capability. The 82840 Memory Controller Hub (MCH) provides the system bus interface, memory controller, AGP interface, hub interface for I/O, and hub interface for PCI bus expansion. This document describes the 82840 Memory Controller Hub (MCH). Section 1.1, Intel® 840 Chipset System Architecture, provides an overview of each of the components of the Intel® 840 chipset.

Intel® 840 Chipset System Architecture
   The Intel® 840 chipset is optimized for the Intel® Pentium® II processor and Intel® Pentium® III processor architectures. The Intel® 840 chipset allows flexibility for dual and multi-processor configurations with 100 MHz and 133 MHz system buses. The Intel® 840 chipset consists of 2 main components: 82840 Memory Controller Hub (MCH), and 82801AA I/O Controller Hub (ICH).

   Architectural expansion is provided with the memory expansion card and PCI 64-bit Hub. The 82803AA Memory Repeater Hub (MRH-R) provides memory expansion capabilities for RDRAM channels. The 82806AA PCI 64 Hub (P64H) provides PCI bridging functions between the hub interface and PCI Bus. The Intel® 840 chipset components are interconnected via an interface called “hub interface”. The hub interface provides efficient communication between the chipset components.