4-pin fan connectors, is the 4th pin needed?

[cubby1223]

I put together a new htpc last weekend and the motherboard doesn't support the smart fan controls to slow down the fan speed. The AM2 Semprons I've always bought always had 3-pin connectors, this one has a 4-pin connector for some reason. A Zalman fan-mate is arriving today and I plan on connecting the regular 3 wires of the cpu fan to the 3 wires of the fan-mate. I'm 99% positive everything will work as needed, but just thought I'd through out a query here.

 

[Ika]

I believe the fourth pin is PWM control, so if you don't want it, you don't need it.