getting good results with these bat files 

r9270x

sgminer.exe -k darkcoin -o stratum+tcp://us.altmine.net:8652 -u x -p x --thread-concurrency 16000 --lookup-gap 0 --gpu-engine 1115 --gpu-memclock 1500 --gpu-powertune 20 -w 256 -I 19 -g 1


7950

sgminer.exe -k darkcoin -o stratum+tcp://us.altmine.net:8652 -u x -p x --thread-concurrency 20400 --lookup-gap 2 --gpu-engine 1100 --gpu-memclock 1500 --gpu-powertune 20 -w 256 -I 18 -g 1