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CPU fan connector

This 3-pin / 4-pin connector is dedicated for providing the power source and displaying the CPU fan speed. 

CPU fan 3-pin IDC male connector at the motherboard 

3 pin IDC male connector layout  








Sense tachometer

CAUTION: Do not place a jumper on this connector; serious board damage will result if the 12v is shorted to ground.

Chassis and CPU fans may use either 3-pin or 4-pin power connectors.  3-pin connectors are usually used for the smaller chassis fans with lower power consumption.  4-pin connectors are usually used by CPU fans with higher power consumption

Fan has a 3-pin power connector; desktop board has a 4-pin fan header: 

Note: when using a 3-pin power connector with a 4-pin fan header, the fan will always be on; there is no fan control.

Fan has a 4-pin power connector; desktop board has a 3-pin fan header: 












Last Update: 03 March 2004