An ATX motherboard is a type of computer motherboard that follows the Advanced Technology eXtended (ATX) standard, which was developed by Intel in 1995. It measures 305 mm x 244 mm (12 in x 9.6 in) and is designed to provide a balance of size, expandability, and performance. ATX motherboards typically feature multiple slots for RAM, graphics cards, and other expansion cards, allowing users to customize their systems. The ATX form factor also includes standardized mounting points and power connections, making it easier to build and upgrade computers. Many modern desktop computers use ATX motherboards due to their versatility and support for various components, including CPUs and storage devices.