Just like the heart the motherboard supplies life to a computer, if it fails the computer will no longer function. The System board, main board or motherboard is the most important circuit board inside a computer besides being the largest it also contains the Central Processing Unit or CPU. All the devices inside a computer communicate with the motherboard. The motherboard is the PC's center of activity. It hosts the largest single collection of chips of any PC component and serves as the "street system" for the grid of wires that link all the components, making it possible for them to communicate. The motherboard defines the computer's limits of speed, memory, and expandability. A computer needs more than just a CPU and memory. To function properly it needs devices, such as a keyboard and a mouse. It also needs output devices, like monitors and sound cards, to cope with the powerful graphics and sound capabilities of the programs available today.
A computer also needs "permanent" storage devices, such as floppy disk drives and hard disk drives, to store data when it is turned off. It is the function of the motherboard to provide the connectivity for all these devices, as well as for the CPU, RAM, and support ICs. There are nine major components in a mother board.
1. The Central Processing Unit.
2. The chipsets Northbridge and Southbridge that support the CPU.
3. RAM random access memory to hold data and instructions.
4. Cache memory to speed up the memory accessed.
5. Communication on the system board via the BUS.
6. Slots to connect devices such as a video card, or modem.
7. BIOS which holds configuration to allow a computer to boot properly.
8. CMOS battery which acts as a backup when your computer is shutdown.
9. A power supply which enables the computer to boot and supplies power to all the devices directly connected to the motherboard.
Besides the standard system board found in the average PC or personal computer there are many different types of mother boards such as workstation or server mother boards. These system boards are normally much larger and more complicated with a plethora of slots which enable the workstation or mother board to be more powerful and functional for high demanding processes.
Motherboard Form Factor Size Inception/Age
AT | 12"x11-13" | 1981-1992 One of the first and oldest form factor motherboard |
Baby AT | 8.5"x10-13" | 1988-1997 This is the smaller AT design for ease of installation and removal, and is still available on the market today. |
| ATX | 12"x 9.6" | 1997 to present This is the lager variation if the Baby AT. Most times with a AGP slot and at least 5 PCI slots. |
| Mini ATX | 11.2"x8.2" | Late 1990's Same as the ATX except for dimensions, |
| Micro ATX | 9.6"x9.6" | Early 2000 An Even Smaller ATX with AGP support, |
| Flex ATX | 9"x7.5" | Early 2000 Socket only processors for custom cases. |
| LPX/Mini LPX | 9"x11-13" | Late 1990's Mounts expansion boards on a riser card above the main board, and fits a smaller case design. |
| NLX | 8-9"x 10-13.6" | Some Current Designs, Supports a faster AGP slot, tall memory sticks plus current and future processor designs, accommodates cooler thermal mounting for processor, has improved external connectivity and attaches expansion boards through add-in-riser.
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