Download HD 6970 BIOS. The Sapphire one I linked to will work on all reference design cards from any vendor.
Make sure the BIOS switch on the card is set to the 1 position (pictured further down if you don't know where it is).
Run ATI Winflash, click Save to save your BIOS, so you have a backup in case something goes wrong.
Load the HD 6970 BIOS into Winflash by clicking Load Image, followed by Program.
Let the flashing process complete and reboot your system.
Check the shader count using GPU-Z, it should show 1536. Make sure you use version 0.5.0 or newer, the official 0.4.9 version does not support HD 6900 Series properly. If you see a shader count of 1600, your GPU-Z version is outdated.
To ensure maximized performance open Catalyst Control Center, go to the Overdrive tab and set the PowerTune slider to the +20% setting. The "Testing" section of this article has more data on that.
Check stability in Windows desktop applications and games.
Purtroppo c'è il problemino dell'alimentazione... la 6970 è collegata con 6PIN ed 8PIN mentre la 6950 con due da 6PIN... potrebbe non ricevere la corretta alimentazione..
Hai provato? Io proverei subito, tanto hanno il doppio bios, è una cazzata annullare la modifica. L'alimentazione non è un problema, è sovradimensionato un 6+8 rispetto al consumo della scheda