Alphacool ES 40mm 400-15,000rpm Fan (40x40x28mm) - Two Ball Bearing - PWM (24826)

The Alphacool ES fans were specially developed for use in servers and workstations and, unlike usual, do not offer a 2 or 3-pin DC power connection, but a 4-pin PWM control. PWM control Instead of using the usual 2 cables or the 3-pin connection, Alphacool now uses a modern 4-pin PWM connection for the Enterprise fans, which is supported by more and more server motherboards. The fan always receives full voltage via the 4-pin PWM connection and is controlled by pulse width modulation. This means that the fan can be controlled over a much larger speed range. By controlling the fans in server racks, a considerable amount of energy can be saved. With 0% PWM control, the fans can even be stopped completely.