Did you oc the R9? 16.3 work with the rx480, they were recommended by Claymore after release 9.x But for R9 they best are 15.12.
What do you mean by "picking up the rx 480 as a general one"?
Did you DDU the drivers before installing 16.3?
Did anyone tested different drivers for R9 cards? My vanilla unmodded R9 380 mines 20.5MH/s ETH + 330MH/s SIA with latest 17.6.2, but
I'd gladly revert to 15.12 if I'll mine more