Locking as this thread has gone south, and the user has the information necessary to make a good decision.
For my part, I don't see any reason to believe (or even suspect) there's any inherent long-term danger involved with unlocking a 6950, as it is the SAME CHIP as the one that lives in the 6970.
Personally I don't go around assuming there's risk to doing something w/o at least some semblance of evidence to suggest that there may be a risk. To date, I've seen no such evidence presented by anyone, on this thread, or elsewhere.
Although it's certainly possible that the flash won't work properly when you do it, it does not make sense to me to conclude that there's a risk of harming your card by using it in an unlocked state if the flash is successful.
Also, KP is the only one I've ever seen suggest that there's a 'log of bios activity' that's generated whenever you flash your bios on a 6950. I'm not saying it's not true, but I've never heard of that before, personally.
This all being said, *if* your flashed 6950 card was to completely die, such that you cannot flash it back to the original 6950 bios prior to RMA, you could possibly wind up in a bad situation w/your warranty. The card maker may have a way of figuring out what bios is on the card, even if it's too dead for you to flash it back, and thus they may deny your RMA. But this risk always exists whenever you flash your card's BIOS.
Thus, if you *really* care about keeping your warranty intact, it's probably a good idea to NOT flash your 6950 with a different bios.
Edited by brettjv - 5/23/11 at 4:26pm