What is a motherboard ? Explaining the 7 main components

Motherboard is a Printed Circuit Board (PCB) which basically connects important components of a computer like a RAM, CPU or used to connect other peripheral devices (external devices like floppy disk, driver etc.) to make a computer work.

In this post, we’ll see all the components found on a motherboard and their functions. Like CPU and RAM.

The components found in a motherboard are –

  1. Basic input output system (BIOS) chip
  2. CMOS chip / battery
  3. Memory slots
  4. Central processing unit (CPU) socke
  5. Expansion slot
  6. SATA port
  7. Chip sets

BIOS chip

BIOS chip holds the BIOS program. A BIOS program is the first firmware that runs on the computer when it is turned on. IT basically makes sure if all the necessary components needed to run the computer is present or not.

It does it by first running a test called Power On Self Test, or POST. It also looks for the hard drive, where our actual computer data is stored, to finally boot the kernel, and the operating system.

The BIOS program is written in assembly language, along with some other language which can be understood by the hardware, like C.

NOTE : The hard drive is not a part of the motherboard .

CMOS Chip / Battery

The BIOS requires to store some data, like date time settings, boot sequence and other hardware settings. Even when the computer is turned off. These data are really important for a computer to function correctly. These settings are stored into a special chip in the motherboard called the CMOS chip. This is also sometimes called lithium chip as its made up of lithium.

This CMOS chip is powered by something called a CMOS battery.

Memory slots

Memory slots

Memory slots are places where DIMMs are installed / attached. These DIMMs are some kind of sticks which is in fact the place where RAM is stored. The more DIMMs there are, the more memory your computer can have.

In a typical computer, you might find 2 or 4 slots.

In order to a program to run, it is first loaded to the RAM. Only this data which is stored in the RAM can be accessed by the CPU to process and run the program. So the more RAM you have, the more number of programs you can run.

Central processing unit (CPU) socket

ryzen cpu
A Ryzen CPU

CPU socket, as its name suggest, is the place where the CPU or the processor is attached. The CPU is the main data processing part of a computer. Everything you are doing in your computer, is somewhere corresponding to the CPU.

Expansion slot

expansion slot -motherboard

An expansion slot, also called a bus slot, is where devices / cards which can provide more functionalities to a computer can be connected, like processing power. Examples – Graphics card, Sound cards, network card etc.

SATA connectors

SATA cable

SATA connectors is where storage devices of a computer are attached. Example – SSD, hard drive etc.

Chip sets

Chip sets are nothing but the components which regulate the data flow between different components of the motherboard. Like memory and CPU, or peripherals.

Older motherboards had more than 10 chipsets attached to them. Each were used to connect different components.

After some times, these were condensed down to 2 chipsets : northbridge and the southbridge.

As of now, INTEL has created Platform Control Hub (PCH) , which is basically a single chipset.


motherboard diagram
Lousy diagram of a motherboard

In this post we discussed about different components found in a motherboard and their functions and how they contribute in the working of a computer.

The overall architecture of a mother board may vary computer to computer. Also the components discussed here, might also be built different in different computers. These things are called motherboard form factors.

Here is short article about it.

Not only that, but their might be some completely components too. But the thing you should take away from this, it that these components are fundamental, what you might see in your computer is just a variation of this.