EDIT 30.03.2018. AMD Adrenalin 18.3.4 drivers provides same or better hashrate than Blockchain drivers from Aug.
AMD Have just released a “brand new” driver set called Adrenalin! We have tested its performance on XMR/Monero, for now this is our conclusion.
We dont recommend anyone to Upgrade to the new AMD Adrenalin 17.12.1 drivers. Beta Blockchain drivers from 23. August is still the best one, even though they do have their problems and issues but they still outperforms newer drivers from AMD with integrated blockchain/compute driver.
You can expect around 1100-1400 H/s on Vega 56 and 64, and very high power usage.
We have also tested it on RX550, RX560, RX570 and RX580 Cards, all cards have shown no increase and most had lower hashrate of ~5-40 H/s with the latest Adrenalin drivers, therefor we suggest that you keep blockchain aug23 driver if you are using that one. If you have drivers newer than blockchain aug23 you can try to upgrade, the difference for cards other than Vega`s is minor even though we noticed about 1-4 % decrease in hashrate. These tests where performed on a windows build earlier than 1709.
VEGA USERS: We still recommend Windows 10 without Fall Creators update combined with Blockchain Beta drivers from 23. August and Registry mod. Its currently unbeatable when it comes to performance for Cryptonight, and is highly efficient.