If anybody is looking to get a little more oomph out of your Radeon HD 6950. I have tested on 2 MSI Twin Frozr III PE/OC and i got a pretty substantial upgrade. Just follow instructions and it will work. I did it on my two MSI cards.
PSU : Thermaltake 850Watt
MB : ASUS Sabertooth 990FX
CPU: FX-8150 @ 4.6Ghz
RAM: Corsair Vengeance 16GB 1600Mhz (OC @ 2005Mhz)
SSD: 2xCorsair Force 3 120GB
HDD: 1TB WD Caviar
Graphics Card: 2 X MSI R6950 2GB Twin Frozr III ( Modded to 6970)