What Does a Motherboard Do All Day?

All the other devices in your PC such as the microprocessor, memory, drives, multimedia cards, printer, and monitor all "plug" into the motherboard in one way or another. Once connected to the motherboard, each device is able to send data to the main memory. Main memory is a holding ground for the data and instructions the CPU needs in order to complete tasks. When the CPU requests data, the memory locates it, then sends it over to the CPU via a pathway on the motherboard called the system bus. When the processor finishes processing the data, it sends the result back to the memory, which in turn sends it back to the device that needs it. The motherboard's chipset coordinates and controls the speed and timing of those interactions.

On the right is a diagram of a motherboard. Notice it is made up mostly of sockets, slots, connectors, and ports. The two primary exceptions are the chipset and the BIOS chip, which are built into the board.

The chipset is the most important part of a motherboard; it is largely responsible for the stability and performance of the board, and it determines which features are supported and which are not. Some well known motherboard chipset manufacturers include Intel, Via, SiS (Silicon Integrated Systems Corp.), AMD, and Nvidia. ATI has recently entered the core logic market as well.

The BIOS (basic input/output system) is responsible for booting up the computer when you first turn it on. It also helps control the flow of data between the operating system and hardware devices. Traditionally, the BIOS was on a ROM (read only memory) chip to ensure that its instructions would never be erased. However, all modern motherboards now have the BIOS on flash memory, which enables the BIOS to be "flashed" (updated) if desired. Further, most modern motherboards even have dual BIOS, which is described in more detail in "Special Features" below.