SouthBridge

A typical southbridge/northbridge layout

The southbridge is one of the two chips in the core logic chipset on a personal computer (PC) motherboard, the other being the northbridge. The southbridge typically implements the slower capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. In Intel chipset systems, the southbridge is named Input/Output Controller Hub (ICH). AMD, beginning with its Fusion APUs, has given the label FCH, or Fusion Controller Hub, to its southbridge.

The southbridge can usually be distinguished from the northbridge by not being directly connected to the CPU. Rather, the northbridge ties the southbridge to the CPU. Through the use of controller integrated channel circuitry, the northbridge can directly link signals from the I/O units to the CPU for data control and access.

Due to the push for System-on-a-chip (SoC) processors, modern devices increasingly have the northbridge integrated into the CPU die itself; examples are Intel's Sandy Bridge and AMD's Fusion processors (both released in 2011). In such cases the southbridge is being directly connected to the CPU. Intel's Haswell, expected to be available in 2013, is expected to feature the southbridge on the same package as the CPU for the Ultrabook platform.