As the OS is called Simple you cannot change any overclock or power limit settings! As I been saying in all my post the cards are averaging 177 watts and you cannot change it in Simplemining! The core is overclocked above 1900 MHz. You cannot change it to the stock clock of 1531 MHz or even to the Boost clock of 1721 MHz.
I can tell you my setup but your not going to be able to help. It's SMOS causing the problems
Intel g4400
MSI Z170A G45
Corsair Vengeance LPX DDR4 3000 4 gb
Kingston 16gb USB
6 - MSI GTX 1070 Gaming X
Corsair AX 1200i
Antec Quattro 1000
6 - powered usb risers Ver 006C
1. set ur desired power limit 1st, nvidia oc depends on that (if u had good cooling maybe 150watt for ZEC mining)
2. if it can run stable, start adding value to gpu core.. start with 100
3. what miner did u use, and what variable did u add
and smos is not the problem, i have using it on nv and amd rigs
the only problem i had is, smos doesnt detect my RX VEGA rigs LOL