Here are my settings for my powercolor R9 280x.  I have also set the voltage set at 1.1v

Was getting 715+Kh/s prior to setting voltage lower but temps were always running high.

Lowered the voltage to 1.1v and now fans run about 40% at 70c and get 710Kh/s and a lot less power at the wall.

"auto-fan" : true,
"temp-cutoff" : "85",
"temp-overheat" : "80",
"temp-target" : "73",
"gpu-fan" : "0-80",
"intensity" : "13",
"worksize" : "256",
"kernel" : "scrypt",
"lookup-gap" : "2",
"thread-concurrency" : "20800",
"shaders" : "0",
"api-listen" : true,
"api-port" : "4028",
"api-allow" : "W:127.0.0.1",
"expiry" : "120",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"gpu-threads" : "2",
"gpu-engine" : "1005",
"gpu-memclock" : "1500",
"gpu-powertune" : "20",
"log" : "5",
"queue" : "1",
"scan-time" : "60",
"shares" : "0",
"kernel-path" : "/usr/local/bin"

If this helps anything is appreciated 
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