Platform Controller Hub

The Platform Controller Hub (PCH) is a family of Intel microchips, introduced circa 2008. It is the successor to the previous Intel Hub Architecture, which used a northbridge and southbridge instead, and first appeared in the Intel 5 Series.

The PCH controls certain data paths and support functions used in conjunction with Intel CPUs. These include clocking (the system clock), Flexible Display Interface (FDI) and Direct Media Interface (DMI), although FDI is only used when the chipset is required to support a processor with integrated graphics. As such, I/O functions are reassigned between this new central hub and the CPU compared to the previous architecture: some northbridge functions, the memory controller and PCI-e lanes, were integrated into the CPU while the PCH took over the remaining functions in addition to the traditional roles of the southbridge.

The PCH architecture supersedes Intel's previous Hub Architecture, with its design addressing the eventual problematic performance bottleneck between the processor and the motherboard. Over time, the speed of CPUs kept increasing but the bandwidth of the front-side bus (FSB) (connection between the CPU and the motherboard) did not, resulting in a performance bottleneck.

Under the Hub Architecture, a motherboard would have a two piece chipset consisting of a northbridge chip and a southbridge chip. As a solution to the bottleneck, several functions belonging to the traditional northbridge and southbridge chipsets were rearranged. The northbridge is now eliminated completely and its functions, the memory controller and PCI Express lanes for expansion cards, are now incorporated into the CPU die or package.

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