atx power supplies

The ATX (for Advanced Technology Extended) form factor was created by Intel in 1995. It was the first big change in computer case and motherboard design in many years. ATX overtook AT completely as the default form factor for new systems. ATX addressed many of the AT form factor's annoyances that had frustrated system builders. PC Perspective - Ten ATX Power Supplies Compared. Other standards for smaller boards (including microATX, flex-atx and mini-ITX) usually keep the basic rear layout but reduce the size of the board and the number of expansion slot positions. In 2003, Intel announced the new BTX standard, intended as a replacement for ATX. As of February 2006 the ATX form factor remains the industry standard for do-it-yourselfers; it has however made inroads into pre-made systems, being adopted by computer makers like Dell, Gateway, and HP.

The official specifications were released by Intel in 1995, and have been revised numerous times since, the most recent being version 2. 2[1], released in 2004. 320 Watt 24 volt DC Input PC ATX-12 Style Power Supply: DC Input ATX-12 Style power.

A full size ATX board is 12" wide by 9. 6" deep (305 mm x 244 mm). This allows many ATX form factor chassis to accept microATX boards as well.

Power supply

AT-style computer cases had a power button that was directly connected to the system power supply unit (PSU).