Still, I get the feeling AMD overstepped in its risk mitigation for 14nm finfet. There is no way they would have designed their first round of chips topping out at 230mm if they had known yields would be good.
Why in the world shoot themselves in the foot like this? Maybe they just really don't want to use GDDR5X, which, now that I think about it gives just about the only plausible reason they wouldn't have readied a higher end chip.
It's not just yields. It's volume, production capability, wafer assignments.
What is AMD making on 14nm FF now?
You can bet it's APUs for Sony's PS4K, Xbox Next and the NX.
What else? Well, a LOT of Polaris 11 and 10 for Apple's upcoming refresh.
It's a better use of wafers to make smaller chips, as you can get more chips and more functional chips out of them to meet demand. AMD simply cannot launch a big Vega at the same time as these productions, IMO.
Compare this to NV, we see the same. Most of the wafers will go to GP100 for expensive Teslas, the rest goes to GP104 and GP106. Why don't they launch GP106 at the same time? Why don't they launch GTX GP100 soon? They can't. TSMC 16nm is only scheduled to get up to ~20% THIS YEAR. They are infact behind, because LAST YEAR they claimed to hit ~30% this year, but their recent conference, their CEO revised the figure down.
We all know TSMC wafers are used by many companies, not just NV.