HELP!I've tried using all my dogecoin settings, and even pasting some of the settings here, but have not managed to break more than 11 KH/s with vertminer

My tried-and-true settings for dogecoin on my 7850 usually give me 346 KH/s:
-intensity 12 --gpu-threads 2 --gpu-engine 1000 --gpu-memclock 1200 --shaders 1024 --thread-concurrency 4096 --worksize 256
but even with the thread concurrency in half, I still can't get much higher than 12 KH/s.
what am I doing wrong? gpu has 2GB of memory, and system has 4GB of ram.