Having problems with 7950? Low Hash rate? DEAD/SICK?

[Simran]

I have 4 of these http://www.newegg.com/Product/Product.aspx?Item=N82E16814202030

Sapphire 7950 4L Reference card

Issues I noticed with mining:

1. DEAD/SICK in cgminer
2. Won't go above 500-550 kH/s
3. Computer crashing on Linux

I have 2 rigs,

One with 1x 7950, other with 3x 7950 and 1x 6950(Unlocked).

They all kept crashing and what not, but the secret to those high hashrates in the configs we see in the wiki is going in MSI Afterburner and raising the "Power Limit" to either +10 or +20, and of course +20 would be the best hashing. Also changing the clocking would help.

Not sure how to does on Linux :\