Depends on your set up to a point, check on youtube for walkthrough's such as here.
If by settings you are talking about the tuning section, then just spend some time tweaking with the settings and bench-marking it via something like 3D mark etc You will generally get to a point where pushing the dials any higher just gives lower results.
EG:
These are my settings on my Red Devil 6800XT
If I increase the min/max frequency by 50 to 2450/2500 my 3D mark scores will drop a bit. I found for me the settings below yielded the highest/stable results.
Just spend a bit of time with it and once you find the sweet spot save it as a profile so you can load it whenever you want that boost etc
