ITx

ITX is a family of motherboard form factors designed for compact personal computers. The term ITX covers several related standards, the most notable being Mini-ITX, Nano-ITX, Pico-ITX, and Mobile-ITX. The Mini-ITX form factor, at 170 by 170 millimeters, is the best known and has the broadest industry support, while the smaller variants are used in embedded and space-constrained builds.

The ITX family originated with VIA Technologies in the early 2000s as a smaller alternative to the ATX standard. It was designed to balance compact size, reasonable input/output options, and power efficiency for small desktop systems and embedded applications. Since then other vendors have produced boards in the various ITX sizes, with Mini-ITX remaining the most widely adopted.

Typical sizes include Mini-ITX (170 × 170 mm), Nano-ITX (120 × 120 mm), Pico-ITX (72 × 100 mm), and Mobile-ITX (60 × 35 mm). ITX boards share a common mounting pattern and I/O footprint that allows them to fit into dedicated ITX-compatible cases and enclosures, though capacity varies by size. They generally provide fewer PCIe lanes, memory slots, and expansion options than larger form factors, but offer sufficient PCIe, SATA/USB/Ethernet capabilities for compact builds.

Uses include home theater PCs, compact desktops, and embedded systems such as digital signage, industrial controllers, and network appliances. The ITX family remains popular for enthusiasts seeking small form factors with upgradeability relative to ultra-small devices, while tradeoffs include limited expansion and thermal headroom compared with micro-ATX or ATX boards.