You need to use the Ati pixel patcher to bypass the driver signature check with a modded bios on RX 470/480 or 570's or you will have a code 43 error. Just run the patcher after installing or updating the the driver.
Thanks! I've already found it. Curently I have 850H/s (XMR cast). I would like to reach 900H/s but I don't know how is it possible. I used your suggestion and set memory to 2020.