you wanna take a bet. I am confident that AMD gets back to 35 - 40% market share by Q3/Q4 2015 and that AMD will get to 14nm first due to their experience with HBM.
Wow, either of those are some ballsy bets. I wouldn't take those if I were you. AMD can't just retain 15-20% market share in a matter of 3 months. Your estimate of Q3 2015 is completely unrealistic and even Q4 2015 sounds unrealistic. Even if R9 300 series is good, NV can easily release 960Ti, 970Ti and refresh 980, while at the same time dropping prices. Did you see NV's margins as of late? 54-56%. NV could probably drop the price of a 970 by $100 and 980 by $200 and still make more $ than AMD.
If NV wanted to, they could undercut the entire Maxwell series so much it would literally make it impossible for AMD's R9 300 series to compete. Why? Because NV has so much cash and almost no debt that they could practically make their market share go to 95% and bankrupt AMD. Luckily NV isn't interested in 15-20% margins and because they are aiming for > 50%+ margins that they haven't completely obliterated AMD by now. Realistically speaking, if NV really really wanted to, they could price GTX980 for $149 for 12 months straight and then GP204 for $149 for another 12 months, on purpose to just bankrupt AMD's GPU division. NV could survive this due to their cash reserves. Believe me, NV has all the cards in its hands, no matter how good R9 300 series can be. That's because financially, NV can withstand the price war - AMD cannot.
Those AIB presentation slides also have 390X as 65% faster than R290X.
If they want to sell it for $799 for the 8GB version, I would buy it. Take my money!
Hopefully the 390 4GB version comes in at ~50% faster than R290X for $499. Sweetspot for bang for buck for non 4K users.
Are you already at 4K, or moving to a 4K screen this year?
If they really want to clear out the 2xx series cards, they should bundle a game. They used to have bundles left and right, what happened to that?
There are no good games games in the near future to bundle - Project CARS, TW3, they are GWs titles. ()

AMD missed its chance to optimize for GTA V and bundle with that game. It would have sold them quite a bit of cards but I think it would cost way too much $ to make it worth it. In Canada the stock of R9 290/290X cards has almost dried up. I think it's a matter of time before the U.S. is hit with it. Our stores here aren't replenishing stock of R9 290 series at all. Once they sell out, they are done. The SKUs are completely removed from the online inventory of the stores.
People who think Maxwell GM200 is unbeatable are probably underestimating AMD R9 390X. AMD R9 390X with the next gen GCN built on GF 28SHP will be impressive at both stock and overclocked. I have high expectations from GF 28SHP vs TSMC 28HP as its a less leakier process with better performance at same power or reduced power at same perf.
Even if all of that is true, NV can respond with a price war the likes AMD has never seen. See my response to Silver above. Secondly, you can't take back that millions of people already upgraded to Maxwell and those customers are lost for another 2-4 years as far as their upgrade path goes. If R9 300 desktop cards are competitive but they are lacking in perf/watt, then R9 300 mobile won't get many design wins come Skylake/Windows 10 Q3-Q4 2015 and more sales to NV. For example, I fully expect the summer 2015 MacBook Pro laptops to be refreshed with Maxwell, not R9 300 series. It's hard to say what's going to happen with the Mac Pro because Maxwell is lacking double precision performance but the 12GB of VRAM would be a huge selling point for Apple to use Quadro GM200 cards in the Mac Pro. Reading on some Apple forums, the R9 M290X/295X got too much negative feedback which makes me think the next iMac refresh will also get Maxwell.
All the new cutting edge laptops coming out like the
Asus UX501 - all Maxwell GPUs.
Even if R9 300 is great, if AMD can't execute with solid supply, it won't get design wins with OEMs. With NV, we know they can deliver millions of products at the customers demand. Winning new business isn't about just bringing out a new card - NV understands this better today than AMD does.