P4 motherboard

I have a question. My P4 mb has a power,system and cpu fan
terminal pin connector on the board. The cpu fan is obvious
as to its function. What is the other two terminal for?
My fan at the front that is blowing air in is connector directly
to the power cable adapter.

Do i need one more fan eventhough my cpu temp is OK and
i have no overheating probs. I have two HD, 1 cdrw,1 cdrom
1 omega zip. The two HD are on a controller ata133 card.

Btw, my board is gigabyte 81dx.

Thanlks.

 

You don't need to use it. A lot of motherboards come with additional three wire fan headers. Only advantage is being able to control fan speed and monitor your fans over the standard four wire plug fans

 

Thank You.