Northbridge in Motherboard (Explained)

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What is Northbridge?

The Northbridge is one of the two chips in the motherboard inside the computer that helps in connecting the CPU or the Central Processing Unit to the major parts of the system.

Apart from that, the Northbridge also connects the Southbridge to the motherboard and thereby helps in controlling the other vital parts of the computer as well.

KEY TAKEAWAYS

  • The Northbridge in the motherboard connects the CPU to the motherboard.
  • This IC is also called the PAC or PCI/AGP Controller or an Integrated Memory Controller and manages the communications between the memory, CPU and AGP.
  • It also connects the Southbridge in the motherboard and allows faster access being closer to the CPU.
  • The faster components on the motherboard such as the RAM, ROM, CPU, video card, BIOS, and even the cache if available are also controlled by the Northbridge.

Understanding Northbridge in Motherboard

What is Northbridge in Motherboard

The Northbridge is typically an Integrated Circuit that is also referred to as the PAC or PCI/AGP Controller or an Integrated Memory Controller or IMC.

This chip is responsible for managing the communications between the CPU interface, memory and the AGP.

Ideally, it is known to all that the CPU is the most vital part inside the computer but the Northbridge is equally important because it acts as the primary controller.

This is because it manages the flow of data to and from the memory of the computer system.

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The primary function of the Northbridge is to control the data and direct them to and from the Central Processing Unit.

The Northbridge is connected to the CPU directly, unlike the Southbridge which is connected to the Central Processing Unit via the Northbridge.

This means that the Northbridge typically acts as the bridge between the Southbridge chip and the CPU helping it to communicate with the memory of the system and the graphics controller.

These days, you will find the Northbridge as a single chip located at the top or the north of the PCI bus, which is why it is called the Northbridge.

However, if you consider the design of the yesteryears, there were even up to three different chips that together made up a Northbridge.

However, in some of the modern motherboards the Northbridge is replaced with hub architecture, just as the Southbridge.

Ideally, when the processor needs data from the Random Access Memory of the system, it sends a request to the Northbridge memory controller.

This responds to the request after receiving it by letting the processor know how long it will have to wait till the memory is read over the FSB or the Front Side Bus.

Ideally, the Northbridge works constantly and therefore needs more power to operate and therefore generates more heat in comparison to the Southbridge.

Therefore, it is not uncommon for a Northbridge to have its own heat sink.

The Northbridge chip is situated close to the CPU and therefore allows easier and faster access.

It also allows it to control the faster components on the main board such as:

  • The RAM
  • The video card and
  • The CPU.
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If on the motherboard the CPU cache is found, then this will also be controlled by the Northbridge.

All these components are connected through dedicated paths called the buses.

This means that the speed of the buses is an important parameter that will determine the overall performance of the computer system.

Therefore, after all these, it can be said that the Northbridge is an equally important, if not more important, component on the motherboard as the CPU.

It actually dictates which particular type of RAM and CPU can be used on the main board.

It also determines the overclocking ability of the chip along with the features that a computer may have and the type of support it will provide to the new technologies.

This is important because there is a limit to overclocking a CPU.

This is because like all other digital circuits, it is also dependent on several other physical factors such as:

  • The storage time of the transistors and its rise, fall or delay
  • The current gain in bandwidth
  • The propagation delay and
  • The parasitic capacitance.

All these also increase the operating temperature which calls for better thermal solutions for the die.

Typically, the whole system is dependent on the Northbridge specifically because only one or a couple of Southbridge chips can be paired with a specific type of Northbridge chip.

Functions

One of the most significant functions of the Northbridge is to connect the Southbridge to the Central Processing Unit.

Also referred to as the Memory Controller Hub, the Northbridge also handles the data transfer by the faster components of the motherboard such as:

  • The Random Access Memory or RAM
  • The Read Only memory or ROM
  • The Basic Input Output System or BIOS
  • The Accelerated Graphics Port or AGP
  • The Peripheral Component Interconnect or PCI Express and
  • The CPU of course.
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The Northbridge also plays a significant role in the bus speed and therefore is used more often than not as the baseline to evaluate the operating frequency while overclocking.

It is due to this particular reason this particular chip also plays a very significant role in determining the extent up to which a computer can be overclocked.

Where is the Northbridge on the Motherboard?

As said earlier, the Northbridge chip is located closer to the Central Processing Unit and towards the top or north of the motherboard.

What are the Components Connected to Northbridge?

The Northbridge is directly connected to the CPU as well as other important components in the computer system such as the RAM or system memory, the Front Side Bus, the AGP card and the PCI Express cards.

Conclusion

To wrap up, it can be said that the Northbridge is a very important component on the motherboard that determines different aspects of the performance of a computer system overall.

Thanks to this article, now you know how exactly this particular chip helps in transferring data to and from the most vital parts.

About Taylor Swift

Taylor SwiftTaylor Swift, a UOPEOPLE graduate is a freelance technology writer with in-depth knowledge about computers. She loves to play video games and watch movies when she has no writing assignments. Follow Her at Linkedin