AMD graphic cards has been very popular for mining, specially for ethereum mining. They have been best price per has and hash per watt since ethereum launch. Previous generation cards (RX 470 and RX570) was widely used on mining farms. Also the latest generation cards RX5700 has now been very efficient for mining ETH. I do understand that Profit is still very low to invest in GPU mining rigs, better choice would be to purchase coins now. But if the markets returns where it was in 2017/2018 , this would be the mining card to choose. As they are quite efficient.

So the test bench i have :

Best Results for mining Ethereum  got from this setup with 100 accepted shares:

  • 640 mh/s
  • 1770 watts

There is settings to add in Phoenix ethereum miner :

  • -openclLocalWork 128
  • -openclGlobalMultiplier 4096

By adding these 2 values to configuration you would be available to reach up to 70mh/s per GPU but with 30-50% invalid shares. Tried to change OC on graphic cards but that does not help.

Video :