I wonder what the exact CPU models will be? Microsoft seems to be taking clues from Apple's guidebook and doesn't bother with stating the exact CPU model even in 'Tech specs'. Likely the Y-series of the latest 6-gen (Skylake) mobile i5's [1] and i7's [2]. They are not released nor announced yet, but the Surface Book is not exactly shipping, either.

[1] https://en.wikipedia.org/wiki/List_of_Intel_Core_i5_micropro...

[2] https://en.wikipedia.org/wiki/List_of_Intel_Core_i7_micropro...