got the same card
tc 21568
i 19
engine 1100
memory 1250
powertune 10
g 1
look up gap 2
w 512
Gets me 462khs stable under 75c
so try
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_USE_SYNC_OBJECTS 1
-I 19 -g 1 -w 512 -–gpu-fan 85 –-lookup-gap 2 –-gpu-engine 1100 –-gpu-memclock 1250 –-gpu-powertune 10 –-thread-concurrency 21568