Wait, so the regular reference card actually clocked higher than this OC special...
Yes, but it doesn't hold that clockspeed.
The MSI Gaming X also doesn't hold the max clockspeed even before it reaches a 82C throttle point. Pascal clocks fluctuate a couple of bins, constantly, as you can see in the graph below this box in the review. The MSI Gaming X *does* get a much higher clock median of 1912mhz, which is what you should consider the realistic clock at gaming loads. The FE will fall off much further - it peaks higher, and falls back more immediately when it hits the 82C throttle point.
With Pascal there is not going to be any easy way to keep a solid boost clock. Where Kepler/Maxwell would dabble in one boost bin up or down, with GPU Boost 3.0 you set a clock range across all voltages.
About the actual OC capability, I was completely right in saying that Nvidia has eaten up most of the OC headroom on Pascal by shipping with very high stock clocks. MSI takes another good 8% of OC headroom and balances it out with their cooling solution. What is left (before overvolt!) is about 8% more performance. That's about 17-20% from stock clocks without boost. Factor in GPU Boost 3.0 however, and you can see most of the OC'ing is done for us.
About the additional pins: I think these cards will peak for typical use at 2100mhz, regardless of overvolt, additional pins or whatever exotic marketing AIB's conjure up this time. Overall I think MSI's Gaming X is going to be the sweet middle ground in terms of a very decent factory OC with a whisper quiet cooler on top, without being overpriced in the whole scheme of AIB releases. They've got a winner methinks.
What I am most curious about is if they will put this exact same cooler on the 1070 Gaming X... in that case, that may be my next card when the prices settle a bit. So far it puts the Asus Strix to shame at least, and Gigabyte isn't even on my list anymore, their cooler needs a lot of love.
(We need an emoticon of clutching the chest)
