Im getting too much rejected percentage
before 60 min - 5% rejected
before 50 min - 20% rejected
before 40 min - 0% rejected
before 30 min - 28% rejected
before 20 min - 13.3% rejected
before 10 min - 8.9% rejected

I have Sapphire R9 290 tri-x

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
C:\cgminer\cgminer.exe --verbose --scrypt -o stratum+tcp://eu.clevermining.com:3333 -u xxxxxxxxxxxxxxxxxxxxxxxxx -p x --thread-concurrency 20481 -I 20 -g 1 -w 256 --gpu-fan 50 --temp-overheat 85 --lookup-gap 2 --gpu-engine 1000 --gpu-memclock 1350


please give me some suggestions

thanks