Guys i manage to get voltage control working i installed latest amd driver 17.7.2 then installed the DAG file on top and used the wattman to set voltages clocks and etc
got back from 27,5mh/s / 750mhs to 29,1mhs/ 830mh/s im dual mining eth + dcr
works like a charm just be carefull if you change the load on the claymore using + or - you have to reset the voltage in wattman
IM using an rx 470 4gb from msi with custom made timings and 1250/2000@ 950mv