Northbridge & Southbridge: 9 Differences

By Dominic Chooper on July 29, 2022

There are basically two chips in the logical architecture chipsets. These are called the Northbridge and Southbridge. Though the primary purposes of the two are the same, but there are certainly some differences between the two.

Right from the location or placement of these two chips from their functionality, there are several other particular aspects that differentiate the Northbridge from the Southbridge.


The 9 Differences Between Northbridge and Southbridge

Differences Between Northbridge and Southbridge

1. Location

The Northbridge is located at the top of the motherboard, while the Southbridge is located at the bottom of it, and hence their respective nomenclatures.

2. Connection

The Northbridge of the chipset is connected to the CPU or the Central Processing Unit of the computer directly.

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On the other hand, the Southbridge is connected indirectly to the CPU via the Northbridge.

3. Purpose

The primary purpose of the Northbridge is to manage the communications between the processor and the other parts of the motherboard.

On the other hand, the purpose of the Southbridge is to manage the input and output functions.

4. Nearby Component

The Northbridge is placed near the processor which allows easier and faster access.

On the other hand, the PCI is the nearby component of the Southbridge.

5. Communication Speed

The Northbridge can communicate faster between the desired components but, in comparison the Southbridge is comparatively slow in communicating.

6. Alias

The Northbridge is also known by different names such as Host Bridge and memory controller hub since it controls memory.

On the other hand, the Southbridge is also known as the I/O controller hub since it handles input-output functions.

7. Bus Performance

The buses that are connected via the Northbridge work much faster like the Accelerated Graphics Port or AGP buses.

On the other hand, the buses that are connected through the Southbridge work much slower like the ISA or the Instruction Set Architecture.

8. Size

The Northbridge appears bigger in size while, in comparison, the Southbridge is much smaller.

9. Components and Ports Connected

The Northbridge connects different components such as the AGP, CPU, and RAM.

However, in comparison, the Southbridge connects PCI, USB, BIOS, SATA, IDE and other ports and components.

Which is More Important – Northbridge or Southbridge?

Well, both these chips, Northbridge and Southbridge are necessary and both have different purposes to serve.

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Therefore, it cannot be said that the Northbridge chip is better than the Southbridge chip or vice versa.

A bit more explanation about these chips will make things clear to you.

Ideally, the Northbridge is considered to be the main bus circuitry of the chipset.

It provides adequate support and manages different other vital components such as:

In addition to that, the Northbridge is typically a single larger chip, which however can be more than one depending on the design, which supplies the alpha designation and distinction to the chipset in its family.

For example, the chip FW82439HX is the particular Northbridge chip of the Intel 430HX chipset family.

On the other hand, the Southbridge involves the controllers related to the peripheral devices as well as those controllers that are not the most vital ones for the basic function of the computer system. For example:

Typically, the Southbridge is a single chip and is therefore most common among all manufacturers as well as among all different variations within a chipset family, for example, the Intel PIIX and the SiS 5513 Southbridge chips.

Ideally, both Northbridge and Southbridge refer to the data channels to the CPU.

As for the Northbridge, it acts as the conduit for the data stored in the memory and the hard disk to flow to the Central Processing Unit.

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And, in comparison, the data input from the keyboard, mouse, CD ROM flows through the Southbridge to the CPU.

Also, the Northbridge refers to that part of the motherboard that connects the faster I/O buses to the system bus as opposed to the slower I/O buses connected by the Southbridge chip.


Therefore, after reading this article you now know that the Northbridge and the Southbridge are two chips on the motherboard that together control the data flow from the memory and other peripherals to the CPU.

The Northbridge is the fast end and the Southbridge is the slow end of the hub.