This is my hashrate and stale share percentage in Claymore 11.6
https://image.ibb.co/iz6vBc/ETC.pngPhoenix can tap my RIG up to 395Mhs (13GPU) however, it gives me 5-6% stale share..
i like the hashrate spike from PhoenixMiner, but i guess effeciency goes to Claymore 11.6 - hope that PhoenixMiner could catch up soon..

Your screen shot doesn't show the stale shares (%). what you are seeing is Valid Share/Rejected Share/Bad Share. Even with v2.7c I only had 2.6% stale, after updating to 2.8c its down to 0.58%. And your Rejected shares are quite high 3 rejected in 404 valid, I have 0 rejected and only 0.01% invalid. So something is not right in your configuration.