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.

You`ve got Zotax 1080 ti, right? Are you using any additional external fans to cool backplate of your gpus?

That`s a truly good example of how your shouldn`t keep your cards. I`m not trying to be rude, just a simple tip. Btw, I also have 5 x 1080 ti and I know what kind of heat they generate.
Ask folks here about their GPU average clock and temperature, because right now you are not only killing your gpus, you also lose money due to overheat when mining.

There`s one exception: u`ve got air conditioner located just above this case.

They are good for nothing. If you have a small case, usage of FE inside of it will kill Video Card way faster than at usual rate.

And what 1080ti are u using? I guess it`s not Founder`s edition for sure, right?

5 gpu = around 2050-2100 Mh/s . But it`s damn hot + I use 3 founder edition gpu, which have dumb cooling system. With proper cooling my system would give standart 2300 Mh/s.

Hi guys, hope u can enlighten me a bit,
Since 01.08.17 - 5 AM and till 04.08.17 - 2 PM (= 81 hours) I was mining Lbry on suprnova and so far have only 86 coins, though I was supposed to get 109 coins .
My rig is made of 5 x 1080 ti and whattomine shows average 32.6189 coins per day = 97 coins in 72 hours with 2000 Mh/s hash rate (my average rate is even a bit higher).
My miner is cc miner 2.1

What am I doing wrong here?