A motherboard is a PCB with expansion capability that contains the processing elements of a computer system. This includes: processor, memory, memory connectors, power management, fixed external interfaces and peripheral bus connectors. Peripherals that can be plugged into a motherboard include devices like network interface cards (NICs) and graphics cards. Single board computers contain all the components of the CPU system. They are usually not customizable by the addition of peripherals, and may include a power supply subsystem. They are used in all manner of products including vehicles, kitchen appliances, televisions and calculators.

Motherboards utilize standard connectors and electronic interfaces for interoperability with peripheral cards (for example PCIe). DRAM memory interfaces using (DIMM) connectors are provided for easy upgrade. Hard drive peripherals and DVD media players connect via other interface standards like SATA. USB and other generic interface connections are usually integrated to allow for mouse, keyboard and audio peripherals. Single board computers may have similar features to a motherboard-based system, but are not designed for upgrade or configurability. They integrate fixed functionality that may be application specific, and typically focus on size and cost by including only devices required by the system and reducing connector requirements.