I don't know what the minimum requirement is, and most people don't mention framerate unless they are having a problem, but a couple people who reported playing in 4k resolution had similar specs: Geforce GTX 770 / 780, Intel i7-4770 / 4790, 16GB RAM, Win 7 / 8.1.
4K framerate is terrible (45, with a
GTX 780 Ti) - there have been a few updates since then...
That's about all I get in a quick search for 4k; unfortunately I mention a specific resolution in the suggestions for crashing on startup, so searching on that would give a lot of useless hits.
