I'm a noob, that's for sure. So I have built a rig based on 6x MSI RX470 Nitro+
My hash rate per card is around 25 mhs
Full rig power consumption: 670 -700W

Other specs:

Motherboard: Asrock pro btc
CPU: Celeron 1840 lga1150

So I have read all the pages and my head have just exploded.

Is there a simple way or a trick with my cards just to find the sweet spot between hash rate and power consumption, of course to lower PC and increase HR?

Or to put it that way. What values to change to what to have a baseline to start experimenting?