I'm getting around 550KH/s on my Diamond HD7970 clocked at 1075MHz with cgminer using the following settigs:
"intensity" : "13",
"worksize" : "256",
"lookup-gap" : "0",
"thread-concurrency" : "8192",
"shaders" : "2048",
"expiry" : "120",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"gpu-threads" : "1",
"hotplug" : "5",
One thing I have noticed is that memory clock appears to have absolutely *no* effect on mining speed. This seems contrary to what other people have posted. I've tried clocking memory up to 1575MHz (the max on this card) and down to 750 MHz and there only a few (2-3) KHash/sec variance.
Any suggestions on how to improve my hashrate would be appreciated.