An ATX motherboard is a type of computer motherboard that follows the Advanced Technology eXtended (ATX) standard. It is designed to provide a layout for connecting various components, such as the CPU, RAM, and graphics card. ATX motherboards typically measure 305 mm x 244 mm and offer multiple expansion slots, allowing users to add additional hardware like sound cards or network cards. These motherboards are popular for both desktop computers and gaming PCs due to their versatility and support for a wide range of components. They also feature various ports and connectors, including USB and SATA, to facilitate connections with peripherals and storage devices.