Northbridge - technical definition

The high-speed part of a common chipset architecture in a computer. The Northbridge is the controller that interconnects the CPU to memory via the frontside bus (FSB). It also connects peripherals via high-speed channels such as AGP and PCI Express. The Northbridge may include a display controller, obviating the need for a separate display adapter.

The Southbridge controller handles the remaining I/O, including the PCI bus, parallel and Serial ATA drives (IDE), USB, FireWire, serial and parallel ports and audio ports. Earlier chipsets supported the ISA bus in the Southbridge. Starting with Intel's 8xx chipsets, Northbridge and Southbridge were changed to Memory Controller and I/O Controller (see Intel Hub Architecture).

      Northbridge Connects CPU to:

      RAM
      AGP bus
      PCI Express bus
      Built-in display Adapter


      Southbridge Connects CPU to:

      ATA (IDE) Drives
      USB bus
      FireWire bus
      Serial port
      Parallel port
      Built-in audio

      ISA bus (earlier PCs)