Now with the results of engenieer's prototypes (like you have seen it from Konsta).
I think it shows very well, that the i7-7y75 and i5-7y54 Cpu, we have in the V are very well integrated and can beat others with the same CPU and also some Skylake U processors. Going into multicore I think we can't reach the i7-6650U because of the Y-CPU's TDP limit.
And one other thing you should think of, is that the i7-6650U uses the Intel IRIS Graphic instead of Intel HD, which brings another increase in GPU Performance (when you want to speak of Performance with an igpu ).
But in the end my Point regarding Overall Performance:
Egpu over Thunderbolt 3 isn't possible with the Surface, so we can get a huge overall performance increase with our V.