The motherboard is the largest printed circuit board inside a computer case. All of the components in the computer connect in some way to the motherboard, and it serves as a sort of traffic controller for the data sent to and from the computer's components. A motherboard has connectors for many different types of parts, and the layout of one can be daunting to a person examining the inside of her computer for the first time.
The CPU socket is the array of hundreds of holes or metal plates to which a computer's central processing unit connects. The CPU socket supplies power to the processor and allows data to be sent to and from the processor from the computer's memory.
A typical motherboard has at least two sockets for Random Access Memory (RAM). RAM acts as a high-speed system for temporarily storing the data needed by programs while they are running. When the processor needs instructions, it receives them from the RAM, and when you save a document or file, it goes from the RAM to the hard drive.
Hard Drive Connectors
Generally, a motherboard has at least two hard drive connectors. Current motherboards use Serial Advanced Technology Attachment (SATA) hard drive connectors, which have L-shaped curves to ensure that cables are connected in the correct direction. The older Integrated Drive Electronics (IDE) connector uses two rows of 20 pins each. Some motherboards have connectors for both SATA and IDE drives. The computer's CD or DVD drive also connects to an IDE or SATA interface.
Floppy Drive Connector
Although few modern computers use floppy drives for storage, many motherboards continue to include floppy drive connectors to support legacy devices. A floppy drive connector has two rows of 17 pins each.
Motherboards have connectors for different types of peripherals, usually located on a back plane that remains exposed on the back of the computer case when the tower is closed. The most common peripheral connection is the Universal Serial Bus (USB) connection, while some motherboards also have connections for audio speakers along with ports for FireWire, serial and parallel devices. Some motherboards have additional "headers," or banks of pins, that can be used to connect additional peripheral ports on the front of the computer case.
Add-on Card Connectors
Many motherboards have connectors for computer add-on cards. These connectors are long slots into which the cards are inserted. There are several types of add-on card connectors. Some of the most common include Peripheral Component Interconnect Express (PCIe) and Accelerated Graphics Port (AGP), used mainly for video cards, and conventional Peripheral Component Interconnect (PCI), used for other types of add-on cards such as sound cards and storage controllers.
Every motherboard has at least one power connector. This connector is used to bring power from the computer's main power supply to all of the computer's components. Because some of today's desktop computers have very high power requirements, some motherboards have additional ports for auxiliary power connectors.
On the side of the motherboard closest to the front of the computer case are the case connectors, a bank of pins to which very small wires attach. The case connectors are used for the power and status lights on the front of the computer case, as well as the power button that turns the computer on.