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What is a Motherboard Bus?

Rolando Braza
Rolando Braza

The motherboard bus is a set of wires that allows one part of the motherboard to connect and communicate with other parts of the motherboard, including the central processing unit (CPU). It also serves as an interface between the CPU and various external devices. The motherboard bus can be one of two types — internal and external.

An internal bus serves as the communication highway of the motherboard. It links the different parts of the computer to the CPU and the main memory. Its primary task is to send data and instructions to the different parts within the motherboard, including the external bus.

A computer motherboard.
A computer motherboard.

The external type of motherboard bus, which is also known as the expansion bus, serves as the interface for peripheral devices like hard disks, CD-ROM drives, and flash drives to get connected to the CPU. The shape of each interface is unique. This prevents plugging a device to a wrong port, which could cause damage to the device while being connected to the CPU.

All buses have a control bus, data bus, and power bus. The control bus is used by the CPU to send signals to the different parts of the computer system to keep the actions of the different parts coordinated. The data bus provides the path to transfer data and instructions among the different components of the computer. It is assisted by the address bus, which provides the physical address of data in the system memory to facilitate data transfers. The power bus energizes the different components of the computer system.

Motherboard buses differ in terms of data bandwidth, which refers to the amount of data expressed in bits that the bus can transfer in a single pass. They also differ in clock speed, which is measured in terms of megahertz (MHz) and tells how fast the bus can transfer data. The maximum devices that can be effectively supported also vary among motherboard buses. Finally, a motherboard bus can communicate using either a serial or parallel bus.

Hardware engineers continuously develop new buses with higher speeds to keep up with state-of-the-art CPUs that work faster. Some buses become obsolete, while some others get enhanced. It is therefore a must to carefully review the specifications of the computer system and inspect it thoroughly before deciding to buy it to make sure that the computer is not yet technologically obsolete.

Discussion Comments

I don't think that technology is disposable. It might be for the person who has enough money to replace their smartphone or tablet as rapidly as they release newer versions, but the average person holds on to their technology for as long as possible these days especially if its something they have grown accustomed to and know how to work both inside and out. If anything being able to work on your own motherboard would be the best way you would be able to keep your technology running long after others have abandoned theirs for newer devices.
I don't know that I would be comfortable changing or even opening my PC for performing any tasks related to the motherboard. It's not that I don't trust my abilities; I just prefer having someone who can shoulder the responsibility of dealing with problem should something go wrong. I guess this is what keeps all those computer repair places running and in business.

But the other side of that coin is that since a lot of technology is now disposable as evidenced by the rapid releases of the smartphones and tablets. It almost makes having this kind of work done irrelevant.

I think changing the motherboard for a PC should be something that everyone who wishes to know their computer a little more intimately should do. It helps you to get a feel of what's going on inside your machine, and you find that just from knowing the layout of the motherboard you can pretty much guess what a potential problem is from the sounds the smells and the particular location to other peripherals that are inside the casing.

It also makes you a little more hands on when it comes to problems that might arise with a motherboard component, such as the CMOS battery, the connectors for the DVD/CD drive, the wires that lead from the media card reader or floppy drive, etc.


I have changed a motherboard or two in my lifetime. I think the hardest part is making sure those jumpers on the board are all set properly. If you don't have the original documentation for the motherboard you might have to go searching for those settings online and hope that what you find is correct.

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    • A computer motherboard.
      By: VIA Gallery
      A computer motherboard.