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?
You need to use the ETHEnlargement Pill. That tool will asjust the timing of the 1080ti to give 47+ mh/s.
Most mining os support the pill by defualt.