JHH never said they had yield issues. This is the statement from where everything came from.
Lower than expected yields does not equate yield problems at all. It means just that: yields at that point were lower than expected, and thus their Q1 forecast was adjusted to reflect that. At a later point he still said that yields were much better than previous nodes. Notice the plural, better than previous node
s.
All this confusion is very simple to explain IMO. He is talking about the Q1 FY 2013 forecast, about why their forecast changed from that previousy predicted, why the gross margin would be lower than they first "promised". So he clearly states the capacity problem and after that he points out that yields on the new node are lower than expected and of course much lower than 40 nm yields at that point, which is why he says "That is, I guess, unsurprising at this point," right after mentioning lower than expected yields. Yields and especially capacity of 28nm is nowhere near that of 40nm, but their new chips, must be 28nm and so they'll not be able to meet demand as well as in previous quarters and so gross margin will decline. That's it, that's all JHH said, IMO, it's very clear if you take 2 seconds to understand it.
Another misconception is that only Nvidia has yield or capacity issues, and this is said because AMD said they didn't have any yield or capacity problems, but that's entirely relative. Come on, does anyone really and honestly believe that AMD and Nvidia have to meet the same demand? First of all Nvidia snatched the Apple deal this round, that is a HUGE amount of chips that need to be delivered. And they also said Kepler has more OEM wins than any other Nvidia generation before.
And regarding AIBs:
http://www.neoseeker.com/Articles/Hardware/Reviews/Nvidia_GTX_670/16.html