ATX Motherboard Specs

ATX stands for "Advanced Technology Extended." Intel developed ATX in 1995, and the specifications have since gone through numerous revisions. The most recent revision occurred in 2007, and ATX now stands at version 2.3.Form factor refers to the size, shape and configuration of a motherboard or other hardware component. The ATX form factor in some ways revolutionized computer design; the form factor currently serves as an industry standard.Measurement and LayoutATX motherboards measure as large as 12 inches by 9.6 inches. ATX motherboards allow a user to connect external devices to the computer through an input/output (I/O) panel located on the rear of the system. The location of the processor, memory sockets, front I/O panel, disk connectors and power input are not explicitly specified. ATX motherboards can support up to seven expansion slots.Variants of ATXMicroATX and FlexATX are all relatively common variations of the ATX form factor. Other variations include MiniATX, eATX (Extended ATX) and WATX (Workstation ATX). The MicroATX is smaller than ATX (measuring only to 9.6 inches by 9.6 inches), incorporates fewer expansion slots and requires less power. The FlexATX is even smaller than MicroATX (measuring 9 inches by 7.5 inches) and contains only two expansion slots.VoltageThe ATX originally used a 20-pin P1 power connector to connect the power supply to the board. The P1 power connector includes +3.3, +5, -5, +12 and -12 voltage pins. Due to the evolution of computer technology and the increased need for more powerful systems, ATX motherboards began to include an extra four-pin, 12-volt power connector called the ATX12V power connector. After the edition of PCIe (PCI Express), ATX upgraded to a 24-pin P1 connector, providing additional +3.3, +5 and +12 volt pins. References Form Factors.org: ATX Specification (PDF) The PC Guide: MicroATX and FlexATX Form Factor