FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -3 pin: voltage in, voltage out, RPM, can be set to an exact RPM using voltage control. 4 pin: voltage in, voltage out, RPM, PWM, pulse width modulation, allows the fan to be set to a specific speed without varying the power going to the fan, useful for magnetic bearings or light up fans.

Detailed explanation-2: -It is also possible to install a 4-pin fan on a 3-pin connector. Here the fan runs at full speed, too, provided the type of control has not been modified. Only one PWM signal for all fans can be set with the Case Fan Hub.

Detailed explanation-3: -Both will work as long as your motherboard has 4-pin headers for all the fans. 4-pin tends to be a bit more expensive and allows for greater control of fan speed. always used for CPU fans. 3-pin is generally used for case fans, but you COULD use a 4-pin if you happen to have one lying around.

Detailed explanation-4: -3-pin fans get a variable voltage (between 5V and 12V) to control the fan speed. If your motherboard’s BIOS is set up for PWM fan control, it will be sending that pulse to the 4th pin instead of lowering the voltage. The 3-pin fans will basically get the full voltage all the time.

Detailed explanation-5: -A four pin connector is a little different than the three pin connector since it has the extra (fourth) wire used for controlling and sending signals to the fan, which likely has a chip on it that tells it to slow down or speed up (in addition to the other wires the three pin connector has).