Northbridge computing microchip Southbridge Motherboard CPU

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A northbridge or host bridge is a microchip on some PC motherboards that is connected directly to the CPU (unlike the southbridge) and thus responsible for tasks that require the highest performance The northbridge is usually paired with a southbridge, also known as I/O controller hub.
In systems where they are included, these two chips manage communications between the CPU and other parts of the motherboard, and constitute the core logic chipset of the PC motherboard.


On older Intel based PCs, the Northbridge was also named external memory controller hub (MCH) or integrated memory controller hub (IMCH) if equipped with an integrated VGA memory controller hub (MCH).

Increasingly these functions became integrated into the CPU chip itself, beginning with memory and graphics controllers.

For Intel Sandy Bridge and AMD Accelerated Processing Unit processors introduced in 2011, all of the functions of the Northbridge reside on the CPU. while some high-performance CPUs still (2013) require Northbridge and Southbridge chips.

Separating the different functions into the CPU, Northbridge, and Southbridge chips was due to the difficulty of integrating all components onto a single chip.

In some instances, the Northbridge and Southbridge functions have been combined onto one die when design complexity and fabrication processes permitted it.

The Nvidia GeForce 320M in the 2010 Macbook Air is a Northbridge/Southbridge/GPU combo chip.

As CPU speeds increased, a bottleneck eventually emerged between the processor and the motherboard, due to limitations caused by data transmission between the CPU and its support chipset.

Accordingly, starting with the AMD Athlon64 series CPUs (based on the Opteron), a new architecture was used where some functions of the North- and Southbridge chips were moved to the CPU.

Modern Intel Core processors have the Northbridge integrated on the CPU die, where it is known as the uncore or system agent.

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Northbridge is an Intel chipset that communicates with the:

computer processor

and controls interaction with

 memory,

 the Peripheral Component Interconnect (PCI) bus,

Level 2 cache,

and all

Accelerated Graphics Port (AGP) activities.

 Northbridge communicates with the processor using the

Frontside bus (FSB).

Northbridge is one part of a two-part chipset called Northbridge/Southbridge.

Southbridge handles the input/output (I/O) functions of the chipset.

The Intel Hub Architecture (IHA) has replaced the Northbridge/Southbridge chipset.

The IHA chipset also has two parts:

the Graphics and AGP Memory Controller Hub (GMCH)

and the

I/O Controller Hub (ICH).

The IHA architecture is used in Intel's 800 series chipsets,

which is the first chipset architecture to move away from the Northbridge/Southbridge design.

IHA

Short for Intel Hub Architecture, IHA is the replacement for the Northbridge and Southbridge found on computer motherboards.

 

The IHA is found on all of Intel's 800 series chipsets,

 

 and like its predecessor it has two parts:

 

 the GMCH and the ICH.

 

The GMCH (Graphics and AGP Memory Control Hub) is similar to the Northbridge and helps control the AGP and memory.

The ICH, or I/O Controller Hub for short, is similar to the Southbridge and is responsible for the I/O ports and PCI controller.






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