Think more in terms of what is appropriate for YOUR games.
A GTX970 will run most games well at 1080P.
If your games are primarily multiplayer, then a quad is appropriate.
Otherwise, many games will use only 2-3 cores and will depend on superior single core speeds. MMO, sims, strategy games are in this category.
A i3-6100 @$125 skylake will do very well as a budget cpu.
If you have the funds, a i5-6600K with an overclock is as good as it gets, but it costs twice as much.