The ATX (for Avanced 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. Other standards for smaller boards (including microATX, FlexATX 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 BTX standard, intended as a replacement for ATX. As of 2007 the ATX form factor remains the industry standard for do-it-yourselfers; BTX has however made inroads into pre-made systems, being adopted by computer makers like Dell, Gateway, and HP.

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