2.2.7 Motherboard Form Factors - Notes
The form factor defines the motherboard's shape, layout, compatible case, power supply, and number of expansion slots.
Form Factors
| Form Factor | Size | Max Expansion Slots | Case Compatibility | Common Use |
|---|---|---|---|---|
| ATX | 12 x 9.6 in (305 x 244 mm) | 7 | ATX cases | Standard desktop PCs |
| Micro-ATX (mATX) | 9.6 x 9.6 in (244 x 244 mm) | 4 | ATX or mATX cases | Compact desktops |
| Mini-ITX | 6.7 x 6.7 in (170 x 170 mm) | 1 | ATX, mATX, or ITX cases | Small form factor PCs, home use, mini servers |
Key Things to Remember
- ATX is the standard, most common motherboard size, and it offers the most expansion slots.
- Micro-ATX is smaller than ATX but still fits in many ATX cases.
- Mini-ITX is the smallest of the common PC form factors and usually provides only one expansion slot.
- Nano-ITX, pico-ITX, and mobile-ITX are aimed at embedded systems rather than standard PCs.
- No commercial boards were ever widely produced from the original plain ITX spec; Mini-ITX is the version that reached the market.