The southbridge is a microprocessor that links the northbridge to other parts of the computer, such as the system clock, common PCI cards, hard disks, network interfaces, USB and Firewire devices, and network contacts. The northbridge component, which is immediately linked to the computer's core, is used by the southbridge to transmit and receive data from the Microprocessor.

The southbridge chip does not need to operate as quickly as the northbridge processor because it is not immediately linked to the CPU. However, it must be able to perform well because it handles input from more components. Since it manages the input and output devices on Intel computers, the southbridge is also known as the I/O Controller Hub.