The arctic f pwm forward the pwm signal from the cpu to the whole case ventilation system the entire system is cooled quietly but still offers the superb performance when needed versatile applicable with the standard 25mm frame the arctic f pwm can be applied as intake or outtake system fan silent operation thanks to fluid dynamic bearing and the patented fan holder design the arctic f pwm is not only quiet but also highly durable quick and easy setup via the pwm signal the cpu f