A motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. Also known as the mb, mainboard, mobo, mobd, backplane board, planar board, or system board. The Motherboard is a printed circuit that is the foundation of a computer and allows the CPU, RAM, and all other computer hardware components to function with each other. Below is a graphic illustration of Acer E360 motherboard made by Foxconn, from 2005, with a large number of integrated peripherals. This board's nForce3 chipset lacks a traditional northbridge.

Modern motherboards include, at a minimum:

• sockets (or slots) in which one or more microprocessors may be installed.

• slots into which the system's main memory is to be installed (typically in the form of DIMM modules containing DRAM chips)

• a chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses

• non-volatile memory chips (usually Flash ROM in modern motherboards) containing the system's firmware or BIOS

• a clock generator which produces the system clock signal to synchronize the various components

• slots for expansion cards (these interface to the system via the buses supported by the chipset)

• power connectors, which receive electrical power from the computer power supply and distribute it to the CPU, chipset, main memory, and expansion cards.