motherboard is also known as a main board, system board and logic board. They can be found in a variety of electrical devices, ranging from a TV to a computer. Generally, they will be referred to as a motherboard or a main board when associated with a complex device such as a computer. All other components and peripherals plug into the motherboard, and it’s job is to relay information between them all. Despite the fact that a better motherboard will not add to the speed of your PC, it is still important to have one that is both stable and reliable, as well as supporting all of the components you require in your system.

A motherboard houses the BIOS (Basic Input/Output System), which is the simple software run by a computer when initially turned on. Other components attach directly to it, such as the memory, CPU (Central Processing Unit), graphics card, sound card, hard-drive, disk drives, along with various external ports and peripherals.


Form Factors

For general technical information about non-PC computer and workstation architectures, seeList of Macintosh models grouped by CPUSPARC, and MIPS architecture.

Motherboards are available in a variety of form factors, which usually correspond to a variety of case sizes. The following is a summary of some of the more popular PC motherboard sizes available:

  • PC/XT – the original open motherboard standard created by IBM for the first home computer, the IBM-PC. It created a large number of clone motherboards due to its open standard and therefore became the de facto standard.
  • AT form factor (Advanced Technology) – the first form factor to gain wide acceptance, successor to PC/XT. Also known as Full AT, it was popular during the 386 era. Now obsolete, it is superseded by ATX.
  • Baby AT – IBM’s successor to the AT motherboard, it was functionally equivalent to the AT but gained popularity due to its significantly smaller physical size. It usually comes without AGP port.
  • ATX – the evolution of the Baby AT form factor, it is now the most popular form factor available today.
  • ETX, used in embedded systems and single board computers.
  • Mini-ATX – essentially the same as the ATX layout, but again, with a smaller footprint.
  • microATX – again, a miniaturization of the ATX layout. It is commonly used in the larger cube-style cases such as the Antec ARIA.
  • FlexATX – a subset of microATX allowing more flexible motherboard design, component positioning and shape.
  • LPX – based on a design by Western Digital, it allows for smaller cases based on the ATX motherboard by arranging the expansion cards in a riser (an expansion card in itself, attaching to the side of the motherboard – image). This design allows the cards to rest parallel to the motherboard as opposed to perpendicular to it. The LPX motherboard is generally only used by large OEM manufacturers.
  • Mini LPX – a smaller subset of the LPX specification.
  • NLX – a low-profile motherboard, again incorporating a riser, designed in order to keep up with market trends. NLX never gained much popularity.
  • BTX (Balanced Technology Extended) – a newer standard proposed by Intel as an eventual successor to ATX.
  • microBTX and picoBTX – smaller subsets of the BTX standard.
  • Mini-ITX – VIA’s highly-integrated small form factor motherboard, designed for uses including thin clients and set-top boxes.
  • WTX (Workstation Technology Extended) – a large motherboard (more so than ATX) designed for use with high-power workstations (usually featuring multiple processors orhard drives.