how many watts does it draw? The 3 wire connector on motherboards usually is only good for 3 or 4 watts. I prefer to have no fans powered off the mobo to leave all the juice to the cpu. If you still want to be able to monitor fan speed from software, i'd get the three wire one, and clip off the red and black wires (on the plug side) and wire those up to a molex (4 wire) connector. I'm pretty sure i've seen adapter cables that have all this done already. If its going to be used as a case fan, i'd deff go with the four wire, as a heat sink fan, i'd go with the three and modify it or get an adapter.