Difference Between 3 Pin And 4 Pin Fan Connectors

If you connect a 4 pin fan on a 3 pin socket the fan will run at maximum speed.

Difference between 3 pin and 4 pin fan connectors.

With a three pin connection two are voltage and one is a speed sensor. The 3rd pin feeds rpm information back to the motherboard. The 4th pin sends a signal to the fan to change speed allowing the fan to run slower and. Changes can easily cause the fan to stall or modulate erratically if the voltage isn t correct.

Three wire and four wire fan connectors. Most motherboards have 4 pin for the cpu. 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. A 4 pin pwm fan connector will have four square holes on the front and four wires entering the back.

Connecting a 4 pin fan to a 3 pin socket. The pwm control wire will not be connected so the fan speed cannot be controlled. The pwm fan does not need to rely on the motherboard bios which is more convenient. A motherboard controls speed by intermittingly sending a current pulse to the fan.

4 pin fans or pwm fans don t have this issue as the 4th pin on the fan allows voltage changes to be made more quickly and less erratically. Chassis and processor fans use either a three wire or four wire connector. Line up the guides on the connector to the tab on the socket. The so called pwm line uses the pwm mechanism to adjust the fan speed and the fan voltage is constant avoiding the control voltage to shift.

It will also have three square holes on the front and three wires entering the back. The three wire connectors are for small chassis fans with lower power consumption. 3 pin fans or dc fans are typically worse than 4 pin fans when changes are made to the voltage in order to adjust the speed of the fan.