The motherboard of a computer is hub of everything. It dictates the potential performance and reliability of a PC.
Central to a motherboard is the CPU (central processing unit) socket. This is where a CPU (such as a Pentium or an Athlon) will be placed. Different manufacturers and different CPU models use different sockets. It is important to match a CPU to its socket type.
Two ICs (integrated circuits) connect all the components together. The “north bridge” interfaces with high speed devices, such as the CPU, memory, the PCI bus, and the graphics card. The “south bridge”, on the other hand, interfaces with slower devices, such as the audio driver (sound card), NIC (network interface card) and USB (universal serial bus). Together, the north bridge and south bridge are important components of the “chip set” of a motherboard.
Most modern motherboards have four slots for RAM (random access memory). The north bridge determines the type, speed and maximum amount of memory that a motherboard can use. Note that as long as the type is correct, it is usually okay to use memory that is faster than required. However, doing so does not have any performance gain.
The chipset of many motherboards supply everything that is needed. However, motherboards intended for high-end computing usually do not include the graphics driver. Furthermore, a user may want to expand the capabilities of a computer in the future. Additional “cards” (printed circuit boards with specific functions) can be added to make a PC more useful. Such cards are usually connected by the PCIe (PCI express) bus. Some motherboards may include a PCI bus for backward compatibility.
Hard disk drives connect directly to ports on a modern motherboard. The chipsets of most motherboards support 4 or more SATA (serial ATA) devices, such as hard disk drives and DVD drives. Many motherboards also include the older IDE (ATA) ports and floppy drive ports for backward compatibility. Newly assembled PCs use SATA for hard disk drives and DVD drives, and use USB for floppy disk drives if installed.
The back of an ATX motherboard also includes a variety of exposed connectors. Such connectors include 4 to 6 USB ports, a PS/2 style keyboard port, a PS/2 style mouse port, microphone, speakers, Firewire and Ethernet connectors. These connectors are exposed after a motherboard is assembled in a case for easy access.
A motherboard also has various connectors for unexposed applications. Fan connectors power various fans in a case. A USB connector connects a motherboard to USB connectors on a case. LED connectors are intended for indicators (power and hard disk activities). Switch connectors connect to the power button and the reset button on a case.
Last, but not least, a motherboard has a number of power connectors. These connectors connect to a power supply unit so that components on a motherboard get the proper electrical power to function.