Unlocking Cores - How and What Dangers?

[incurablegeek]

OK, if an AMD 8-core opteron running at 2.0 GHz is really two 6-cores with a total of 4 cores disabled,

1) What is the way to unlock those 4 cores and have a 12 core?  (I know it has been done on lesser core chips)

2) There are many reasons why the Opteron 8 and 12 cores run at only 2.0 GHs (compared to a 3.0-3.2 Phenom).  Is one of the reasons they run at such a slow speed the fact that those 8 cores could contain disabled cores (4) that failed ASUS' testing?