not seen any get that high outside of a HOF on LN2. the fps difference between 2 ghz and 2.1 is less than 1 fps in reality. getting another 50 mhz or so would translate to no perceivable gain real world. other than to say you have it that high, there is no reason to spend a ton of money and spend the time to do it.
the ftw card showed the same in game performance as the sc card despite being so much more expensive. the cards are just so tapped out already there is just nowhere else for them to go. very different from the last gen maxwell cards which could actually see big gains from the expensive cards.