NOTE-one fen is not working one is fine and that is enough for gaming without overclock for me I just set temp limit in msi afterburner to 75 and good to go.using like this for 6 month's
GPU-asus strix gtx 980 dc2oc
https://www.asus.com/us/SupportOnly/STRIX-GTX980-DC2OC-4GD5/HelpDesk_Knowledge/