I just upgraded from a 2500k @4.5ghz to a binned 5ghz 7700k from OcUK this week.
Also got Asus ROG Maximus IX Hero, 2x8gb Corsair Vengeance LPX 3200mhz and Noctua NH-D15.
The 7700k indeed is running at 5ghz as we speak, peaks out in mid 70s under P95 Blend. In games it's in 50s. One game in particular I struggled in with the 2500k was Black Desert Online (BDO). My 2500k ran at 100% CPU usage on all cores and in towns I was getting from mid 20s to mid 40s fps. Now with the 7700k I'm getting 60fps in towns, with drops to low 50s sometimes (depends on the situation, weather, population etc). CPU usage is anywhere between 30%-55% across all of the threads. It feels a lot smoother.
Also tried The Division and I went from around 60fps to 80+fps with the same settings. Haven't had time to try many more games. I am really happy with my upgrade.
Oh, Qnix710 (1440p/120hz/PLS/27"), Zotac AMP! 980ti.