i run a small farm based on 7850s, in cgminer don't specify the shader, or thread concurrency, just put two threads, then 1080 gpu engine and memory 1400. try and let me know the results. in fact here's my current .conf its been running almost a week no crash or shutdown required.
"intensity" : "12",
"vectors" : "1",
"worksize" : "256",
"kernel" : "scrypt",
"lookup-gap" : "2",
"thread-concurrency" : "0",
"shaders" : "0",
"auto-fan" : true,
"gpu-engine" : "300-1080",
"gpu-fan" : "0-100,0-100",
"gpu-memclock" : "1445",
"gpu-memdiff" : "0",
"gpu-powertune" : "0",
"gpu-vddc" : "0.000",
"temp-overheat" : "90",
"temp-target" : "70",
"api-port" : "4028",
"expiry" : "1",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"gpu-threads" : "2",
"log" : "5",
"no-pool-disable" : true,
"queue" : "0",
"scan-time" : "1",
"scrypt" : true,
"temp-hysteresis" : "3",
"shares" : "0",
"kernel-path" : "/usr/local/bin"
i get 380 ~ 400 kh