try this
make a .bat file and put the following in there

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1


cgminer.exe --scrypt -o "xxxurlxxx" -u "user" -p "pass" -I 13 -g 2 -w 256 -shaders 2048

make sure this .bat file is in the same folder as cgminer

run this bat file, you should be in the 650+ range

leave out thread concurrency and vectors