With this adapter you can connect a fan that has a 3 pin molex connector, directly to a 4 pin Molex connector on your power supply. The rpm signal is derived in this adapter separately with a single core with 3 pin molex connector, so you can read out the speed of the connected fan if connected to the power supply on the motherboard. Thus, you still have full control of these fans. The 4-pin power supply connector is NOT looped through this adapter - therefore you will when using this adapter lose a 4 pin power supply connector. With this adapter, the output voltage of 12 volts at 4 pin Molex connector of the power supply is not changed. Thus, no change in connection of the fan arise through this adapter to the power supply compared to the terminal directly to the motherboard.
