I'm using a Sapphire hd7950, which is a 11196-19-20G
It give me 680KH/s for a temp at about 70°C and fan below 60% (56% for the moment)
What could you try ?
1/ First lower power consumtion and undervolt.
Use atiflash to save a backup of the bios of ALL you cards. Don't do anything with bios if you have not backup.
Then use vbe7 to reduce voltage from 1.25 to 1.081 (try 1.113 if too low, depends on the quality of your PSU. I'm using 1.125 now) and TDP from 233W to 200W or less (my hashrate drop below 190W).
try this modified bios on all your cards, including the N°4
2/ try this values: TC 24000, shaders 1792, gap 2, thread 1, temp target 72, vddc 1.125, worksize 256
then try to overclock a bit. I'm using gpu-engine 1100 and memory 1500. Since I've undervolted, temp doesn't go above 70. And since I'm limiting power, it doesn't increase too much to.
3/ increase intensity step by step from 13 to 19 or 20 (stop if hashrate drop)
4/ last, when all is working well, use an optimized scrypt kernel (from 'lantis' or another guy). It give me 30kh/s more