ATX12V

ATX12V is a specification for computer power supplies that extends the ATX standard to ensure adequate, stable 12-volt power for the central processing unit and other high-current components. It defines voltage tolerances, connector layouts, and safety features used by desktop PSUs to deliver power to motherboards, CPUs, and expansion devices.

The standard was introduced by Intel in the late 1990s to address rising CPU power needs by providing a dedicated 12V rail and a CPU power connector. Over time, ATX12V revisions added an 8-pin EPS12V CPU power connector, expanded main power connectors to 24 pins, and updated electrical requirements. The evolution from ATX12V 1.x to 2.x reflects ongoing changes in processor power demands and motherboard designs, with EPS12V and related guidance shaping contemporary designs.

Key technical features include a primary 12V rail for the CPU, multiple 3.3V and 5V rails for other components, a standby 5VSB rail, and defined protection mechanisms such as overcurrent, short-circuit, and thermal protections. Modern ATX12V power supplies also emphasize efficiency and compliance with evolving standards and guidelines, such as higher efficiency targets and, in some cases, Eco or energy-related requirements.

Compatibility considerations include broad backward compatibility with many older motherboards and cases, though very old systems may lack support for newer high-current 12V connectors or higher-wattage requirements. When selecting a PSU under the ATX12V framework, it is important to match system power consumption, especially CPU and GPU loads, with the supply’s available 12V capability and overall wattage, while ensuring connector availability and safety features meet the build’s needs.