BFG Tech combines high performance, high efficiency, and low noise all in a MX-680 ATX12V & EPS12V Power Supply. Thermal Control Technology ensures that the unit runs as quietly as possible by varying the speed of the 120MM fan in response to load and temperature. An 80MM "helper fan" only kicks in when temperatures reach over 50°C to ensure maximum performance, longer life, and low noise at lower temperatures. Quad +12V rails, over-volt, over-current and short circuit protection provides rock solid reliability and safety.