leave the stock one in it really moves a lot of air.  but if it slows down to 1200 rpm it is not that loud.  just add a good  second fan.

  I have some photos. This one shows how to add the second fan

how to power it I cut these

http://www.amazon.com/Syba-SY-CAB65007-Female-Connectors-Extension/dp/B002G1YNQS/ref=sr_1_5?ie=UTF8&qid=1398513944&sr=8-5&keywords=y+fan+cable

and add to the antminer




and the slower speeds on the stock fan