An ATX case has a cutout for the motherboard's integrated input/output ports.
The form factor, or shape, of computer components is an important consideration when selecting computer parts. Since the case holds all of a computer's internal parts, its form factor is especially important. AT and ATX are two case form factors.
Significance
As of 2010, ATX motherboards are the most popular type. In a computer system, the motherboard and case form factors must match. Therefore, you cannot mount an AT motherboard inside an ATX case, and vice versa.
Changes
The newer ATX case integrates all the input/output ports into the motherboard, while AT cases only integrate the keyboard port. The ATX case also supports a more efficient and simpler power supply connector than the AT.
Benefits of ATX
The ATX case improves on the AT case in several ways. ATX cases are configured to hold larger memory modules and expansion cards. The power supply in an ATX case is positioned so that it blows air over the CPU, to enhance cooling.
Tags: case form, case form factors, form factor, form factors, input output