A motherboard provides the connection between all other computer parts. Processors are attached directly to the motherboard, and the RAM, peripherals and storage devices are attached as well. Motherboards themselves, however, perform no computation and do not store information.
Computers are created with distinct parts that play different roles. Processors perform calculations, and the RAM stores the information the processor needs. Hard drives and other storage devices do nothing more than hold information, and peripherals instruct the operating system. The role of the motherboard is to provide connections between these components.
Motherboards are designed for specific types of processors and specific types of RAM. Users can often upgrade some components, but most eventually need to upgrade to a newer motherboard. Motherboards also provide USB ports and ports for connecting video and sound cards.
While motherboards are often believed to be the "brains" of a computer, they do nothing on their own aside from providing power for individual components and providing connection. A motherboard cannot function without a processor, RAM and other components. However, users may sometimes wish to upgrade their motherboards. New motherboards support more RAM. In addition, upgrading to a new motherboard allows users to use more ports and connections for peripherals.