Processor Fan Wiring Diagram. The four wire connectors are for processor fans with higher power consumption. When connecting a three wire fan to a four pin fan header the fan is always on.
Chassis and CPU fans may use either 3-pin or 4-pin power connectors. In a 3-wire fan first two wires are the power supply wires of the fan. FAN POWER AND GROUND.
I know I have to hack off the useless Dell proprietary connector but what I want to know is can I power the 12V and GND from a 4-pin molex and then just wire the fans sense and PWM to the mobos PWM fan header.
Note that Chassis and CPU fans may use either 3-pin or 4-pin power connectors. With the help of this third wire a monitoring circuit can see the rotation. Fans and on-board fan headers are backwards compatible. The four wire connectors are for processor fans with higher power consumption.
