The most easily used are the fan headers built into the mobo, which provide both power and speed control of the fan. The speed they run at is determined by the fan controller they are connected to. And of course, that Mode also controls 3-pin fans, so it appears to be a "universal" controller. They can ignore Pin #4 and use only the older Voltage Control Mode, and depend on the backwards compatibility feature of the 4-pin motor design to make that work. Many controllers and almost all mobos use 4-pin headers but do NOT always use the new PWM signal system. You can NOT tell from the number of pins on the output headers. OP needs a simple fan controller that uses only the older Voltage Control Mode. BUT it receives from Pin #2 the VARYING voltage, and hence its speed IS controlled in this manner. Of you plug a 4-pin fan into a 3-pin header, the fan gets no PWM signal to use so it cannot modify current flow. You get good cooling but no way to slow the fan down.
Be quiet silent wings 3 pwm full#
If you plug a 3-pin fan into a 4-pin header, the fan will always receive the full +12 VDC supply from Pin #3 and will not get the PWM signal it could not use anyway, becasue it lacks the special chip. So you CAN plug either fan type into either header type and it will work - sort of.
![be quiet silent wings 3 pwm be quiet silent wings 3 pwm](https://m.media-amazon.com/images/I/71QmlDIgjOL._AC_SL1500_.jpg)
To establish as much backwards compatibility between these as the PWM design was introduced, the electrical signals were kept as similar as possible and the mechanical design of the connector also is very similar. Inside the fan, a chip uses that signal to modify the flow of current from the +12 VDC supply line through the motor windings to achieve speed control. The extra Pin #4 delivers to the fan the Pulse Width Modulation signal. In this system, Pin #2 always has the full 12 VDC. The newer design are called PWM fans and they use 4 pins. The older one is the 3-pin system in which the voltage supplied on Pin #2 varies from 12 VDC max down to about 5 VDC min - lower may stall the fan.