I understand that Claymore miner is done now, but using 1080 Ti cards with every other miner I get ~18MH/s instead of ~47MH/s if the DAG is over 4GB in benchmark modes (win 8.1). What am I missing? Linux works well so I'm guessing it's some driver or windows limitation? Is there a workaround?
I had same problem, for 2 weeks

..now i solved this issue!. You have to run Gminer
https://github.com/develsoftware/GMinerRelease/releases