Northbridge (computing)

The Northbridge is a hardware component of a modern PC motherboard. Traditionally, the North Bridge is a separate chip, which in contrast to Southbridge densely located on the CPU to transfer data quickly. The two chips (North and South Bridge ) are collectively referred to as the chipset. A need to provide the Northbridge as a separate chip, but there is not ( Recent Developments ).

Intel refers to some of his northbridges as a memory controller hub (MCH ). The processors on Nehalem - based, the term describes the Uncore integrated in the processor Northbridge functionality among others.

Typical tasks

The task of Northbridge is the synchronization and control of broadband data transfer with the lowest possible latency. Therefore, it is in the control hierarchy far above: So it connects, for example, the main processor to the graphics card, in older motherboards it is also responsible for the exchange of data between main processor and memory, but this is no longer common, as the main processor and the memory are directly connected. The other peripherals are usually connected only indirectly via a link to the Southbridge. Due to the high data throughput, the northbridge has to cope with normally, it must be designed in accordance with broadband and high- clocked. Therefore, in most cases, cooling is necessary.


Since the processor core can communicate with the rest of the system must, must exist a remote station for him who understands the bus protocol and translates the data transfers and passes on. This is one of the most important tasks of the Northbridge. Typically, this connection is realized as a front side bus ( FSB), that is, it is designed as a bus to which a plurality of processors to participate. However, there are also developments that use a bus instead of a point - to-point protocol, such as Hyper Transport and QPI.

Memory controller

The Northbridge contains inherently at least one memory controller to control the memory and to make available to the system. Depending on requirements, the multi-channel controllers (eg, dual-channel controller) can also be other controller to support different types of memory (eg DDR and DDR2 SDRAM). In this case, they would often be used only exclusively (one time).

Connect the graphics card

Devices are usually connected via the southbridge, but there is a popular exception: the graphics card. Since the connection to this usually very broadband fails, usually the Northbridge contains the control logic in the form of an AGP or PCI - Express port or an integrated graphics unit. The PCIe x1 slots are, however, in turn connected by the Southbridge.

Connection to the Southbridge

To connect more equipment to your system, the Southbridge is usually used. The connection between the Northbridge and Southbridge was previously realized via the ISA or PCI bus, later they sat for reasons of speed on proprietary point-to- point connections. Since the advent of these amplified PCI-Express is used.

Recent Developments

Since the 2000s, the North Bridge is gradually as a separate chip on the decline: processors like the AMD Athlon 64 or Intel Core i7 for speed reasons already integrate some or all parts of Northbridge, creating a separate chip is no longer necessary. Then, even though the chipset only remains over the South Bridge, one also speaks here of a chipset.