According to some accounts, it is at least 3 or 4 times more "manufacturable" that Itanium.
That would very uneducated accounts. The Opteron has many cost/yield/manufacturing disadvantages compared to Madison:
- SOI processing - less mature process - more interconnect layers - high speed I/F needs new ATE investment; likely source of non-trivial parametric yield loss
The only advantage of Opteron is it's about half the die size of the Madison. But if you compare compare critical die size (the area of the chip occupied by non redundancy protected structures and circuits) the two chips are much closer in effectice size for yield considerations than raw size indicates.