spokeshave, keep in mind that speed bins are also important when figuring out how well AMD's is producing parts. Even though that doesn't technically fit into the definition of yields, it's just as important when it comes to determining AMD's ASP, and hence their revenues.
Also, unless AMD had some massive market share gains in a shrinking market, there is no way they could be selling 8M CPUs per quarter these days, much less from one fab.
Tenchu