No it won't. This gen, a 0.5TFlop (1.8 vs 1.3) difference made a noticeable difference in the end. With next gen, a 0.5TF difference will be almost unnoticeable (don't expect a higher difference than 0.5-1TFlop, as both fight within the same power envelope). If/when both consoles are around 10TFlop (of "Navi - TFlops"), a few % difference just doesn't cut it.
It will boil down to "Who shouts louder?" and who has the better exclusives.
If PS5 comes out and is 8 Tflops, and the xbox is 9.... it wouldnt even matter.
At 4k those differnces will be minor.
Resolution stuff is much more noticeable at lower resolutions.
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071