even with fan being powered and / or PWM controlled from different source. Tachometer signal is on pin-3 and has nothing to do with variable voltage or PWM control.Īny fan with pin-3 rpm signal can have that lead plugged into 3-pin or 4-pin fan header on pin-3 to monitor rpm of that fan. Most motherboard 3-pin fan headers are not pulsed 12v power. The motherboard pulses signal send from fan, then fans' built in PWM circuitry pulses 12v power from whatever source it is coming from to motor. PWM fans with 4-pin plug do not pulse the PWM signal. They are misleading consumer by using 'PWM control' differently than 'PWM' is used on PWM fans. Powered directly by SATA cable from the computer power supply and.

Motherboards that are claiming to have PWM control but only have 3-pin headers are doing what you said and saying they have 'PWM fan headers' are playing games with consumer. It is capable of expanding one motherboard PWM fan header to support up to eight fans. to fan' is not the way PWM is supposed to be done. Click to expand.PWM control is supposed to be only for 4-pin PWM fans.

Pwm fan hubs