Temperature around 60 degree during mining is impossible without water cooling or powerfull external air conditioning. My guess: something is wrong  with sensors of your Zotacs.
Let`s assume that you significantly decreased power voltage and gpu core clock. You`d lose around 25-30% of power to make it happen, but decreased voltage would make your system highly unstable, so once again - something is wrong with your sensor or you are using external air conditioning.