use this and report back

setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
cgminer --scrypt -o stratum+tcp://www.xxx.zz:1234 -u me.1 -p x -I 13 -g 2 -w 256 --thread-concurrency 8192 --gpu-engine 1010 --gpu-memclock 1350 --lookup-gap 2 --gpu-powertune 20 --auto-fan --temp-target 72