(Advanced Technology EXtended motherboard) The PC motherboard that superseded the Baby AT design. The ATX layout rotated the CPU and memory 90 degrees, allowing full-length expansions to be ...

The most mainstream and common motherboard form factor, ATX was created by Intel in 1995. The typical size of an ATX motherboard is about 9.6" x 12". EATX: 13" x 12" -- A fully-featured ATX ...