A motherboard is the major, underlying circuit board of a computer. The Central Processing Unit (CPU), Random Access Memory (RAM), and various disk or optical drives are all plugged into interfaces on it. A video interface and sound card can also be built-in or added, and additional connections are used by peripherals and various devices.
Purpose of Motherboards
One of the major functions of a motherboard is to act as the "hub" to which other computer devices connect. A board can come in many configurations to fit different needs and budgets. At its most basic, it has several interfaces for necessary components and numerous microchips that control computer startup. Many computer enthusiasts favor one type of board over another and choose a manufacturer based on the firmware installed on it or the types of hardware it supports.
Numerous chips and components are physically installed onto a board, including the north and south bridge. These are two chipsets that are used with the CPU to allow communication between the processor and memory. All important components are connected either directly or indirectly to the board, so it serves as the "nervous system" of a computer.
Motherboards and Processors
An important feature of a motherboard is the socket used to house the CPU. Different types of sockets are found on various boards, with different configurations for the processor pins. These fit into the socket, allowing it to act as the primary processor of a computer.
Motherboards typically support a specific type of CPU, such as a processor made by AMD™ or Intel™. Among the processors available, there are different grades of CPUs. An AMD™ 64-bit processor requires a different CPU socket than an AMD™ 32-bit processor. Someone purchasing parts to build a computer needs to ensure that the CPU and motherboard are compatible.
RAM and Different Boards
Motherboards also impact the amount and type of RAM that users can install in a computer. It is often best for someone to use a board that supports more RAM than he or she needs. If new technology for RAM is available, getting a board that supports the newer type can help future-proof the hardware. There are different types of RAM available, indicated by terms such as "Double Data Rate" (DDR) or "Dual In-line Memory Module" (DIMM), with new forms being introduced fairly regularly.
Boards also have a limit on the total amount of RAM they can support. It is important for someone to choose sticks of memory that do not surpass this limit. Each stick may also have a memory limit set by the type of board used, which is indicated in the manual for a board provided by the manufacturer.
Expansion Slots and Drive Connections
The number of Peripheral Component Interconnect (PCI) slots varies from one motherboard to another, which can include an Accelerated Graphics Port (AGP) specifically designed for video cards. These slots are used to connect peripheral components within a computer case, such as video and sound cards or modems. New formats are often introduced that improve connection speeds, so older motherboards might not support newer hardware.
Boards also have a number of Serial AT Attachment (SATA) ports or Integrated Drive Electronics (IDE) connections for use with hard drives and optical devices. Much like other connections on motherboards, these change over time as new technology is introduced. Adapters may be useable in some instances, though it is typically necessary for a new board to be used when connecting a drive with newer attachment cables.
Size and Power Supply
A motherboard also comes in one of a few standard footprints or sizes. This can impact the type of system case in which the board fits. Many motherboard manufacturers also recommend particular power supplies that have been tested with their hardware. It is important that a sufficiently large supply of power is used with a board, and that the power supply has the right kind of connections to plug into it.