Computer motherboard components and their functions

A computer motherboard is also known as the main circuit board, logic board, or mainboard. It is the main printed circuit board on the computer

It carries most of the computer components like CPU, RAM, BIOS, BUSes, CMOS, chipsets, cache memory, jumper, and many other components. The motherboard’s main function is to house the component and provide means of communication for various parts.

computer motherboard

5 functions of computer motherboard

Being the main circuit board motherboard has many functions and is mostly the most crucial.

1. The motherboard houses other components

The main function of the mainboard is to house the computer components. Most of these components are inbuilt while others can be removed or changed at will. In one way or another, all computer components both internal and external have to interact with the mainboard.

2. Computer components communication

For a computer to function all parts must communicate. The motherboard offers BUSes which are used to transfer data from one component to the next. There are SATA and IDE cables that help in data transfer with the mainboard. 

3. It is a backbone for basic electronic circuit

A computer being an electronic device needs electronic gadgets like capacitors I.C., resistors, and all the other devices for effective operation. Mainboard offers the circuit to connect those components and make a computer a functional electronic device. Without the motherboard then no functional computer.

4. Offers peripheral connectors and ports

The motherboard comes with inbuilt ports for external devices. This allows devices like mice, keyboards, and others to be connected to the motherboard for communication. They also have expansion slots to add more functionality to the computer. 

5. Supplying power to components

For all the electronic devices on the motherboard to work they need power. The motherboard has a slot that is used to get the power for the computer’s main power supply system. This ensures that all components housed on the mainboard are powered.

14 computer motherboard parts and their functions 

1. CPU socket

CPU or the computer processor socket is placed on the motherboard for communication with other devices. The socket allows the insertion of a processor or change for another one if need be. Each CPU is specific to a given motherboard hence the reason to check before trying to change it. If you put the CPU that is incompatible with the motherboard it will not work.

There are two types of sockets meant for different CPUs. One is a socket with holes where the pins on the CPU are supposed to move into. It is known as PGA for Pin Grid Array. Care should be taken when dealing with this type because pins may be broken.

The other type doesn’t have pins instead they have copper pads that are aligned with the socket on the motherboard. It is called LGA (Land Grid Array)

2. RAM slots

This is where the main memory of the computer is placed. Again depending on how the slot is designed not all RAM can be used in any motherboard. It depends on how the motherboard divides the section of the socket. Most computers have 4 slots for the RAM.

3. CMOS battery

It is used to ensure the BIOS contents are not lost and to keep the date and time even when the computer is switched off. The battery can be changed if it expires.

4. BIOS (Basic Input Output System)

It is a ROM memory that stores the basic computer setting and has a program that initiates the booting of a computer.

5. Chipset

They are Integrated circuits that control data flow between the CPU and other components. They can either be North Bridge or south bridge. In some of the computers, these chipsets are integrated into the CPU and hence cannot be seen, mostly on the North Bridge.

The North Bridge (memory controller) allows communication between the CPU and main components such as RAM and video card. 

The South Bridge (input-output controller) communicates between the CPU and input-output devices, the expansion cards, the drives, and devices connected through their ports. Most chipsets today have a heat sink to cool them.

We have a more comprehensive article on chipset architecture, functions, and types that you can read. 

6. Data connector

Depending on the types of connector the motherboard support there are different connectors. IDE data connectors were used in old PC but today computer comes with SATA connector. SATA is smaller in size.

The connector connects from the device to the motherboard. The connectors are for all devices (mostly the hard disk and CD/DVD drive) that need to communicate with the CPU.

7. Power connector

The motherboard has a slot for connecting the power from the main power supply of the computer. Other components that have a direct power connector are Hard disks and DVD/CD drives. All other components are powered from the mainboard and not directly from the main power.

8. Expansion slots

These are used to upgrade the computer by adding an expansion card to give more functionality to the computer. Depending on the motherboard you can have a PCI, AGP, or PCI Express slot. PCI Express is the fastest and the latest. The card can be a sound card, TV card, game card, etc.

9. Ports /connectors

All the ports used to connect external devices are soldered to the motherboard. They include an Ethernet port, USB, HDMI, VGA, DVI,  PS/2 for keyboard and mouse port, and any other that the motherboard supports.

10. Jumper pins

These are small pins protruding from the motherboard. Changing the cap from one pin to another can change the circuit flow of some parts of the system.

11. Switches

They are small electronic switches within the board. They can be used to turn on or off a circuit within the mainboard depending on user requirements. They can be turned on or off by the use of a small screwdriver to avoid damaging them.

12. Cache memory

These are high-speed memories that are used to speed up the access of data to the processor. They are 2 levels Level 1 which is inbuilt with the processor and Level 2 cache which is standalone.

Level 2 or the secondary cache is the component of the mainboard since level 1 is part of the CPU.

13. CPU clock

It is a component that controls the timing of all components of a computer. It controls the processor time allocation of different processes and also keeps system time.

14. Heat sink

This is part of the computer cooling system to ensure components don’t overheat. The main heat sink is positioned on top of the processor with a cooling fan. It removes heat from the processor which is then blown away by the fan.

Common computer motherboard form factors

The motherboard’s size and layout are known as the form factor. There are many form factors for different computers designed. The form factors are designed for different purposes, there are 3 main which include standard ATX, Micro ATX, and Mini ITX.

Most of the main components are the same for any form factor e.g. they can take the same CPU, the back connection ports are the same and many other components can be used in any if they belong to the same family.

The only main difference is that the Standard ATX can carry more additional components than the other (it is good for a future upgrade than the others). Another difference is the power supply and the casing for each may be a bit different. The casing for Standard ATX can be used by others.

1. Standard ATX form factor

This is used by most manufacturers which means they are found in many computers. They are the biggest compared to the other two. This means they can have more components than the other. For example, they can have more expansion slots and more RAM slots compared with others.

2. Micro ATX form factor

This is the second in line in terms of size. It is bigger than Mini ATX but small than the Standard.

3. Mini ATX form factor

It is the smallest of the three form factors available for general PC. It can be used in other cases because it can fit well, but other cannot use is casing.

Factors to consider when replacing computer motherboard

1. Form Factor and casing

Depending on the function of the computer that you are building you will need to consider the form factor. Again it will depend on the casing you have, if you have one for Mini ATX then you cannot get other types of motherboards.

2. Type of CPU Socket

Different motherboards are designed for specific CPUs. Check with the motherboard manufacturer to know which CPU your motherboard can support. Check to ensure you know the type of processor supported either  PGA for Pin Grid Array or LGA (Land Grid Array) before buying the motherboard.

3. RAM slots

Depending on how the slot is divided will determine which type of RAM the motherboard can support. RAM may fit on the slot but it may not be compatible with the motherboard so it is good advice to check before you buy a new RAM that is not compatible.

4. Expansion Slots

Depending on the future upgrades that you will need you may check the number of expansion slots available and their type. Computers with PCI Express are the latest and better than PCI and AGP.

5. Input/output ports

Check the available ports that can be used to attach the input and output devices. Most devices today are connected through the USB port, so you may need to check how many USB port the motherboard support. Also, you may choose one that offers the port of the device that intends to use.

6. Built-in components

Most of today`s computers have their components in-built into the motherboard. This makes them more compact. Check for components that you may need built into the motherboard and see if they are available.

7. Processor speed

Different mainboards are designed to operate at different speeds depending on processor speed. Ensure the motherboard can work with the processor speed that you have.

List of motherboard Manufacturers

Motherboards are built by many companies, most of which have been in the industry for a long time. They are many in the market but some of them include

  1. ASUS
  2. Intel
  3. Gigabyte Technology
  4. DFI and AOpen 
  5. Biostar
  6. MSI

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