If you are trying to unlock a card anymore that's been bought recently, the chances for success are about zero. In the beginning a few got out there with good pipes, but they are binning those GPU's and they are not gonna put a good 16 pipe working GPU on a standard card. If they are locked, they are locked for a reason...they are broken.
Personally I wouldn't even attempt it. If I wanted a 16 pipe card, I'd buy one. Running the voltage up will help OC's, but will do nothing for unlocking a broken pipe. If it's broke, it's broke. In fact, it will probably create more heat, and cause it to artifact quicker.
The only real reason people were having cards unlock before, is because there were so mnay good ones massed that had all 16 pipes working that some of them got binned for the cheaper cards, but that is rarely the case anymore. It really doesn't matter what company makes the card. They are not gonna bin good 16 pipe GPU's for 12 pipe cards.
Occasionally somebody may luck out, and get one that slipped past, or was weak but they all still worked, but the chances are slim to none.
