Motherboard Form Factors

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The motherboard form factor describes its shape, layout, and the type of case and power supply that can be used, plus the number of adapter cards that can be installed.

Advanced Technology eXtended Form Factor

he Advanced Technology Extended (ATX) specification is the standard form factor for most desktop PC motherboards and cases.

• Full-size ATX boards are 12 inches wide by 9.6 inches deep (or 305 mm x 244 mm)
  • can contain up to seven expansion slots
• Micro-ATX (mATX) standard specifies a 9.6-inch (244 mm x 244 mm) square board
  • maximum of four expansion slots

Information Technology eXtended Form Factor

Small form factor (SFF) PCs are popular as home machines and for use as mini servers.

SFF PCs often use Via’s Mini-ITX (Information Technology Extended) form factor.

• Mini-ITX is 6.7 inches (170 mm x 170 mm) square
• one expansion slot
• designed for small cases
  • but most mini-ITX boards can be mounted in ATX cases
• There are also smaller nano-, pico-, and mobile-ITX form factors
  • used for embedded systems and portables