actually performs better on my 280x and 7950 ....
Tried it. I lose 4 Mh per card.
Interesting I gain about 500KHs on both cards
I'm not using pool but am solo mining ...
Here's my config for sgminer 4.1.0-103-g00015 :
"intensity" : "18,20",
"worksize" : "256",
"kernel" : "groestlcoin",
"lookup-gap" : "2",
"thread-concurrency" : "8192,8192",
"shaders" : "2048,1792",
"gpu-threads" : "2,1",
"gpu-engine" : "1100,1100",
"gpu-fan" : "30-100",
"auto-fan" : true,
"gpu-memclock" : "1700,1300",
"gpu-memdiff" : "0",
"gpu-powertune" : "0",
"gpu-vddc" : "0.000",
"temp-cutoff" : "95",
"temp-overheat" : "85",
"temp-target" : "64",
"api-mcast-port" : "4028",
"api-port" : "4028",
"expiry" : "60",
"failover-switch-delay" : "60",
"gpu-dyninterval" : "7",
"gpu-platform" : "0",
"log" : "5",
"no-pool-disable" : true,
"queue" : "0",
"scan-time" : "59",
"tcp-keepalive" : "30",
"temp-hysteresis" : "2",
"shares" : "0",
"kernel-path" : "/usr/local/bin"