The reference GTX 980 and GTX 970 use the much lauded Titan cooler, which does a very good job at keeping temperatures below the 82 Celsius mark, while remaining reasonably quiet during gaming. The fan speed went fluctuated from 1140RPM at idle to 2058RPM when gaming. Nvidia cooler is the ideal solution for reference clocked GTX 980 cards and it is pretty hard to improve upon. It will definitely be interesting to see what have Nvidia AIB partners prepared for the custom and factory-overclocked GTX 980 graphics cards.

As you can see, the Boost clock went up to 1240MHz (Base clock is 1126MHz)

The default temperature limit on the GTX 980 card is set at 80 degrees Celsius. The cooler does a pretty good job and the temperature never exceeds 81 degrees Celsius. This basically means that the card will reduce the Boost clock once it hits the threshold, staying within the thermal envelope without revving up the fan.