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Older layout with a separate northbridge

The South Bridge is a hardware component of a PC - motherboard (also called motherboard or mainboard). It is located close to the PCI slots in order to establish an electrical connection as quickly as possible. In addition to the northbridge, the southbridge is an important part of the mainboard. The two chips are also known as a chipset .

SIS964 next to the PCI bus slots
Southbridge on a mainboard


The data transfer and data control between peripheral devices ( PCI bus , ISA bus , ATA etc.) and other interfaces takes place via the chip in the south bridge . In addition, with modern mainboards, part of the periphery is often already integrated on the southbridge, e.g. B. the USB controller. South and north bridges communicate either via PCI or PCI-X , a proprietary interface (such as VIA's V-Link) or free industry standards such as the HyperTransport interface of the HT consortium. As a rule, the chips of the southbridge are slower than those of the northbridge and are therefore used for the slower work such as e.g. B. the energy management (e.g. control of the standby mode), interrupt controller, BIOS EEPROM, network controller, etc. are used. She is also entrusted with the control of the USB interfaces.


In Intel terminology, the Southbridge is now known as the I / O Controller Hub (ICH). In a narrower sense, this means the Intel 82801 chip.

In the variant of the Nvidia nForce4 chipset intended for AMD K8 processors , southbridge and northbridge function blocks are integrated on a microchip.

AMD uses the term Fusion Controller Hub (FCH) as part of the AMD Fusion concept . For AMD Fusion, all Northbridge-typical functions were integrated into the microchip of the main processor. In the FCH, Soutbridge-typical peripheral interfaces with comparatively low bandwidths such as SATA , USB, LPC , HD-Audio and PCIe × 1 came. The FCH and the central processor chip are connected to one another via a serial interface, the so-called Unified Media Interface (UMI).

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