Hello could someone help me

I have 4 R9 280x cards and only have between 250-270khs with this bat file

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
exeminer --nscrypt -o stratum+tcp[Suspicious link removed].poolz.net:3333 -u x -p x -I 13 -g 2 -w 256 -v 1 --thread-concurrency 8193 --lookup-gap 2 --gpu-powertune -20

What is it that doesnt work?