North Bridge is one of two chips in the main board chipset of PC based on Intel processor. North Bridge is designed to process high-speed signals. It usually processes the ports of CPU, memory, PCI Express card (AGP card in the early years), high-speed PCI Express x16 / X8, and communication with South Bridge.
South Bridge is one of the chips based on the chipset architecture of PC motherboard. The South Bridge is designed to process low-speed signals, and is connected with the CPU through the North Bridge. Different manufactures of chipset have different name for this component. For example, Intel calls it the input / output controller hub (ICH), NVIDIA calls it MCP, ATI calls it IXP / SB, AMD also begins to incorporate fusion APU, and gives it marks as FCH, or Fusion Controller center, on behalf of its South Bridge chip. However, in some chipset architectures, the functions of South Bridge will be integrated with those of North Bridge; or some functions will be moved to North Bridge, while some functions of South Bridge will be deleted, and the deleted interface functions will be provided with additional independent chipsets. In this way, there will only be a single chip in the whole chipset architecture, and there will be no other South Bridge chip.