It depends on the games and settings, some of the newer games are far more CPU-intensive, with the most intensive ones scaling all the way to an overclocked i7-6900k/6950X.
Most games are far more GPU-intensive than CPU-intensive and will be fine with a more mainstream CPU. With Ryzen only a week away, you may want to wait for Intel's price adjustments before buying anything if you plan to build in the very near future.