Form Factor
A motherboard by itself is useless, but a computer has to have one to operate. The motherboard's main job is to hold the computer's microprocessor chip and let everything else connect to it. Everything that runs the computer or enhances its performance is either part of the motherboard or plugs into it via a slot or port.

A modern motherboard
Photo courtesy Consumer Guide Products
A modern motherboard.
See more computer hardware pictures.

The shape and layout of a motherboard is called the form factor. The form factor affects where individual components go and the shape of the computer's case. There are several specific form factors that most PC motherboards use so that they can all fit in standard cases. For a comparison of form factors, past and present, check out Motherboards.org.

The form factor is just one of the many standards that apply to motherboards. Some of the other standards include:




You've probably heard the term motherboard a thousand times, but do you know what it really means and how it relates to the rest of your computer?

The form factor of a motherboard determines the specifications for its general shape and size. It also specifies what type of case and power supply will be supported, the placement of mounting holes, and the physical layout and organization of the board. Form factor is especially important if you build your own computer systems and need to ensure that you purchase the correct case and components.

The Succession of Motherboard Form Factors




What is a Motherboard?:

The motherboard serves to connect all of the parts of a computer together. The CPU, memory, hard drives, optical drives, video card, sound card and other ports and expansion cards all connect to the motherboard directly or via cables.

The motherboard can be thought of as the "back bone" of the computer.
The Motherboard is Also Known As:

mainboard, mobo (abbreviation), MB (abbreviation), system board, logic board
Important Motherboard Facts:

Motherboards, cases and power supplies all come in different sizes called form factors. All three must be compatible to work properly together.

Motherboards vary greatly in respect to the types of components they support. For example, each motherboard supports a single type of CPU and a short list of memory types. Additionally, some video cards, hard drives and other peripherals may not be compatible. The motherboard manufacturer should provide clear guidance on component compatibilities.
Popular Motherboard Manufacturers:

ASUS, AOpen, Intel, ABIT, MSI, Gigabyte, Biostar
Motherboard Description:

The motherboard is mounted inside the case, opposite the most easily accessible side. It is securely attached via small screws through pre-drilled holes.

The front of the motherboard contains ports that all of the internal components connect to. A single socket/slot houses the CPU. Multiple slots allow for one or more memory modules to be attached. Other ports reside on the motherboard which allow the floppy drive, hard drive and optical drive to connect via ribbon cables. Small wires from the front of the computer case connect to the motherboard to allow the power, reset and LED lights to function. Power from the power supply is delivered to the motherboard by use of a specially designed port.

Also on the front of the motherboard are a number of peripheral card slots. These slots are where most video cards, sound cards and other expansion cards are connected to the motherboard.

On the left side of the motherboard (the side that faces the back end of the case) are a number of ports. These ports allow most of the computer's external peripherals to connect such as the monitor, printer, keyboard, mouse, speakers, phone line, network cable and more. Most motherboards also include USB and FireWire ports here that allow compatible devices to connect to your computer when you need them - devices like digital still and video cameras.

The motherboard and case are designed so that when peripheral cards are used, the sides of the cards fit just outside the back end, making their ports available for use.
Related Articles

* Component Profiles - Motherboard, CPU, RAM, Video Card, Hard Drive
* Inside Your PC - The Motherboard
* DIY: Installing a Desktop PC Motherboard
* Video Card - What is a Video Card? - Graphics Card - Video Adapter - NVIDIA...