so...
- ati official driver do not work with windows 7, but work good on windows 10 (i have win7)
- unofficial modded driver work good on win7 and win 10 (but can not be sure if it is clean)
- both drivers break overclock compability, wattool and afterburner not work (even with new beta afterburner it not change everything)
- overdriveNtool work for new driver, have voltage but have no offset
- peoples saw increase of power, but it is just result of broken oc tools, they do not change voltage
conclusion - i will stay on old driver and wait for problems to go away ..
I too could not get official driver to work with Win7, but the unofficial robinh00d driver works.
Afterburner beta #16 gave me clockspeed and voltage control for RX 470 and 480 using the robinh00d drivers
(have not tried with 570 yet)
Voltage changes are not applied immediately, takes effect when mining is paused/restarted.
Also it seems that changes to clocks end up resetting the effective voltage back to default, so make the voltage changes the final thing you apply.