In dark souls you still get like 2 health after lv 50, Upgrading from an 15 4960 to even an i7 5820k will only somtimes give you 1 frame.
It does depend on the game sometimes but this is correct, most games barely scale past 4 cores except for very heavy multithreaded ones like GTA V, Battlefield 4 (multiplayer) you can also choice to get a cheaper xeon e3 1231 which is a 4core hyperthreaded chip (essentially the I7 4770 without an igp) thats the silicone its based off. It's useful if you video edit or play those games where every extra thread helps and costs less than an i7.
In most cases an i5 4690k or the i5 6500k (not sure on the skylake models off the top of my head) overclocked is really the best option for gaming becuase you get basically the best singlethreaded performance and also very solid multithreaded performance.
Before someone says Xeons arent for gaming, that depends on the xeon you are talking about
theres $25000 models and $300 models.
Thats what I chose to power my rig, its the same 1150 socket as the i7 4790 so if I really wanted to I could upgrade to that but the performance gain wouldn't be worth it.