4PinFans

4PinFans refers to computer cooling fans that utilize a 4-pin connector. This connector type is primarily associated with Pulse-Width Modulation (PWM) technology, which allows for finer control over fan speed. Unlike older 3-pin fans that typically operate at a fixed speed or rely on voltage control, 4-pin PWM fans can adjust their rotational speed based on the thermal output of the computer's components.

The 4-pin connector has four pins: a ground pin, a +12V power pin, a tachometer pin for reporting fan speed, and a PWM pin. The PWM pin sends a signal that effectively "chops" the power supplied to the fan, creating a series of pulses. By varying the width of these pulses, the fan controller can precisely regulate the motor's speed. This allows for quieter operation when the system is idle or under light load, and increased cooling performance when temperatures rise.

Motherboards and dedicated fan controllers typically have 4-pin headers that can manage PWM fans. The BIOS or software settings on the motherboard can then be configured to set fan curves, dictating how the fan speed should respond to specific temperature thresholds. This dynamic control contributes to both system stability by preventing overheating and acoustic comfort by reducing fan noise. While 3-pin fans can sometimes be plugged into 4-pin headers, they will not benefit from PWM control and will likely run at full speed.