Low end and mid end Pascal is Q2 2016, high end Pascal is Q2 2017
One is the 16nm fab is new...and untested...and you can't go large and power hungry on first generation chips. Don't believe how unreliable a new fab is? Look at how long it took Nvidia to pick between Samsung and TSMC and finally siding with TSMC due to their longer working history and reliability.
Second point is...they will kill their own sales by offering their best card right at the release of the new generation. They will not be able to give any reason at all to their enthusiast market to upgrade their card within 3 years of launch. Whereas when you look at Kepler, people bought the 680, then the Titan came out, then the 780, and most people who bought the 680 eventually upgraded to those cards. And then when Maxwell launched, they started with just the 750 and 750ti. Then released the 980 that some bought, and finally after a while, the Titan X and 980ti which gave people (enthusiast market, again) a reason to upgrade.
Nvidia likes incremental upgrades. They don't want you to buy a card now, and launch another card in a year that completely destroys the card you bought. They put out one card, then 12 months later they bring out another card that is generally just 10-20% faster, so it's better than what they offered before, but not enough to **** off anyone who bought their last gen cards. And then another 6-12 months later they put out an even better card, with 50%+ better performance than their older cards, and people start upgrading again.
If on day one of the Pascal launch, if they come out with their absolute best card, they are going to have nothing interesting to bring to market for 2 to 3 years until Volta comes out. And that would be silly. Even if it were possible with the new 16nm fab. In terms of business, you need to offer a product that is a bit better than your competition, without being too much better/too costly for you. So they just need to put out a slight performance increase, but sell the card on much lower power consumption, wait for AMD to release something else, and then launch a bigger die version themselves, and back/forth they go. Just a quick reference:
FERMI
GTX 580 = 520mm2
KEPLER
GTX 680 = 294mm2
GTX Titan = 551mm2
MAXWELL
GTX 750ti = 148mm2
GTX 980 = 398mm2
GTX Titan X = 601mm2
Do you see the pattern? Small, Medium, Big, restart. Don't think about it based on die size. Because it's really just about transistor count. Pascal at 16nm, even a 294mm2 sized die like the GTX 680, along with HBM2, would result in performance close to the Titan X...and perhaps even higher due to lower heat/power consumption allowing higher clocks.
Hope that helps.
Also, NVIDIA is launching the GTX 990, so it would not make sense to release high end Pascal in Q2 2016
We also know HBM2 is going to have problems with amount of stacks as there was not enough HBM1 for AMD, so if NVIDIA and AMD are using HBM2, there will not be enough (Titan O, will need 16GB HBM2) this is why NVIDIA will have to wait for Samsung HBM2 (which starts production in Q2 2016) so it will take till 2017 for there to be enough and for NVIDIA to implement it on the GTX 1080ti and Titan O
Thanks for reading
