
Originally Posted by
Bagnaj97
You know it unlocks to an X4 because you've done it before and it was stable, or because others have done it on that board? Unlocks are never guaranteed.
Athlon X3s were originally created to make use of X4s with a faulty core - it was only when yields rose that "good" X4s had a core disabled to produce X3s. You have a chance to get lucky, or you get what you paid for - if it's unstable with the 4th core unlocked then the chip isn't broken, you just didn't get lucky.