Southbridge is an Intel chipset that manages the basic forms of input/output ( I/O ) such as Universal Serial Bus ( USB ), serial , audio, Integrated Drive Electronics ( IDE ), and Industry Standard Architecture ( ISA ) I/O in a computer. Southbridge is one of two chipsets that are collectively called Northbridge /Southbridge. Northbridge controls the processor , memory , Peripheral Component Interconnect ( PCI ) bus , Level 2 cache , and all Accelerated Graphics Port ( AGP ) activities. Unlike Northbridge, Southbridge consists of one chip, which sits on Northbridge's PCI bus.
The Intel Hub Architecture (IHA) has replaced the Northbridge/Southbridge chipset. The IHA chipset has two parts also, the Graphics and AGP Memory Controller Hub (GMCH) and the I/O Controller Hub (ICH). The IHA architecture is used in Intel's 800 series chipsets, which is the first chipset architecture to move away from the Northbridge/Southbridge design.