NORTHBRIDGE-SOUTHBRIDGE

11/20/99

Northbridge-Southbridge: A chipset architecture that uses two (sometimes more) physical chips to provide support functions to the CPU. The Northbridge chip(s) connect the CPU, memory, PCI bus, and AGP graphics if it is supported. The Southbridge Chip(s) control peripherals and the ISA bus, if present. It interfaces them to the PCI bus. Typical Southbridge functions are keyboard, mouse, serial port, parallel port, ISA bus, IDE, USB, IEEE-1394 control.

Many Northbridge chipsets will operate with multiple different Southbridge sets and vice versa. There is usually a default Southbridge chipset matched to the each Northbridge chipset. When the chipset is described only by the name of the Northbridge chipset, that usually implies that the default Southbridge is used.

Super-southbridge sets include 2D/3d video, audio, or other enhanced controller capabilities along with the "normal" Southbridge functions.

While the Northbridge-Southbridge architecture is very common with Pentium class and later CPUs, there are other alternatives. For example, the Intel 440MX combines all functions into a single chip.