I have 18 cards nvidia GTX 1060 6GB
Im only getting about 22mh/s no matter what settings i use.
I was first mining at
power limit 80%
max temp 80
mem clock +550
core clock +0
they run at 64-68 C

Now i use them at:
power limit 65%
max temp 80
mem clock +550
Core clock +150
Fan speed 90%
now they run at 67-72 C
Still i get about 22 mh/s each card.
The power usage did go down tough.
They use about 1650 watt. total.

What are the setting you use when getting 25 mh/s stable?