i5-2500k

I'm considering an upgrade from my current i5-2500k to either an i7-7700 or a Ryzen 1700. My needs are purely gaming. I won't be streaming or recording gameplay, will just be playing single player campaign oriented titles. Going by the above which should I pick up between the two? I also won't...

My main PC is an i5-2500K @ 3.3GHz w/ 8GB and a 3GB Radeon 7850 (won on the AT forums several years ago). I mainly play Overwatch on a 27" 4K monitor, obviously with reduced rez. I'd like to be able to bump up the rez/rendering and get a bit smoother framerate to boot, and future-proof this PC...