The motherboard is the centre piece of you system it contains all the circuitry and components either directly on the board or via additional components which connect directly to it. The motherboard is also often referred to as the main board.
The motherboards many connectors and slots include a socket for the processor to be installed along with memory slots, a number of expansion slots, connectors to IDE/SATA devices and smaller connectors for USB, serial and printer connectors.
The motherboard plays an essential role in the following aspects of your computer system:
Organization of devices: Everything is eventually connected to the motherboard. The way that the motherboard is designed and laid out dictates how the entire computer is going to be organized.
Control of the devices: Built-in to the motherboard is the chipset and BIOS program, which between them control the majority of data flow throughout the different computer systems.
System Communication: Almost all communication between the PC and its peripherals, other PCs, and you, the user, goes through the motherboard.
Processor Support: The motherboard socket depicts which choice of processor you can use in your system.
Peripheral Support: The motherboards components determine what type of peripherals you can use in your PC. For example, you can not use AGP cards if you only have PCI slots.
System Performance: The motherboard is a major factor in your system's performance; it dictates which type of processors, memory, system buses, and hard disk interface speed your system can have via its connectors or BIOS settings. Often if you are upgrading after a number of years you will need to replace the board, CPU, and memory.
Upgradeability: As motherboards are developed newer processors may not be compatible with your hardware as limitations of the circuitry built-in to the board itself will not allow them to run. As a result you can look for any upgrades via your maker's website but may need to consider upgrading.
The block of connectors on the motherboard which include the Ethernet, USB, serial, com and mouse/keyboard ports is often referred to as the I/O Panel, the often silver surround which sits between the panel and the outer edge of your system case is called the I/O shield.
Usually PCI to allow for other devices to be installed, AGP cards are used solely for video cards. Newer versions including PCI-Express functions still remain the same.
Here your processor (CPU) is connected to the motherboard. Usually they have a socket design with a lever on one edge once lifted you can insert the processor. Normally a small notch or marked corner indicates the only way that the processor can fit the socket. Once secured the heat sink and thermal paste is installed over the processor and secured into place.
Also known as memory banks as each slot on the motherboard is termed a bank of memory. You will need to check that you are using the right type of memory for you board. They will only fit into the slots one way by noting the notch in the middle of the module and the number of pins on each side. Once the clips at either end have been opened the module can then be pressed firmly into the slot and the clips secured to hold the module in place.
These connect to your IDE devices of either hard drives or CD/DVD Drives or a combination of both. A smaller IDE connector is also used for Floppy disk drives.
Every switch on the front panel of your case including the power switch, reset, power led, hdd led, and any USB ports all need to be connected to the pin outs on the motherboard to function.
Other connectors on your motherboard include additional pins to connect fans to. If you have built-in sound you will also see AUX and CD-in which connect to the DVD drive to allow for playback directly from the drive.