A PWM fan controller can adjust the speed of a fan by feeding the engine with pulses of current instead of reduced voltage. The advantage with this is that you can control the speed of the fan more precise, both manually and automatically. Zalman says it has now launched the world's first PWM-based fan controller, PWM Mate, which is intended to be used with your 4-pin CPU fan, and can control the power of the fan between 25% and 100% speed.

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