I have the same CPU - the settings configuration should be made in the Bios.
Re temperatures. Mine runs from around 52 to 67 degrees C (latter over the recent hot weather) and the Nios is set to cut it off if, by any chance, it reaches 70 degrees C (perhaps due to a failed CPU fan). To cool it off I just turn up the fan speed, which is normally set on minimum.
Maximum permissable temperature is 85 degrees C although I wouldn't like to reach too near that point...:-)