CPU fan third wire

[mongo]

I noticed there are three pins on board for fan in this card:
http://www.amiga-hardware.com/download_photos/gvpgforce040_2_big.jpg

is third pin unused? can I safely connect modern fan with its third, yellow, wire?
or should it be cut?

I would cut it because you don't need it and I don't know what it's connected to on the board.