Every time I try to mine litecoin I get stuck at 6 kh/s and my computer lags majorly. The only problem I have found that fixes this is if I restart my computer then run the program. I have an R9 270x and use CGminer.
setx GPU_MAX_ALLOC_PERCENT 100
cgminer --scrypt -o stratum+tcp://usa.wemineltc.com:3335 -u potatoe422.1 -p x -I 19 -g 1 -w 256 --thread-concurrency 15232 --auto-fan --temp-target 65 --temp-cutoff 85 --temp-overheat 75

I have tried other pools and other miners and they all do the same thing.