I/O Controller Hub (ICH) is a family of Intel southbridge microchips used to manage data communications between a CPU and a motherboard, specifically Intel chipsets based on the Intel Hub Architecture. It is designed to be paired with a second support chip known as a northbridge. As with any other southbridge, the ICH is used to connect and control peripheral devices.
As CPU speeds increased data transmission between the CPU and support chipset, the support chipset eventually emerged as a bottleneck between the processor and the motherboard. Accordingly, starting with the 2008 Intel 5 Series, a new architecture was used that incorporated some functions of the traditional north and south bridge chips onto the CPU itself, with the remaining functions being consolidated into a single Platform Controller Hub (PCH) and therefore replacing the traditional two chip setup.