Comment by DanielHB

I would expect 80% of the failures would have only one core not pass QA.

I remember back in the day it wasn't that unusual for intel to sell quad core CPUs and dual core CPUs that exactly the same hardware-wise, but the dual-core ones didn't pass the QA to be sold as a quad-core.

In fact they sold many functional quad-core CPUs as dual-cores with 2 cores disabled and you could unlock the extra cores with some magic if you got lucky and got one that passed the quad-core QA.