Blauboad, Re: Designing and validating a dual core Opteron is the easy part, considering that Opteron was developed with this in mind.
I don't buy that for a second. Designing dual core takes more than slapping a second piece of logic on a die. AMD may have accounted for some things in the micro-architecture, but that's not the same as having a design ready.
Re: The problem is manufacturing a die that big. They have to wait until the process is mature enough so that producing them is economically feasible.
That's the second problem.