I play DayZ mostly now, so I know which CPUs are best for Bohemia Games.
There are 3, which I personally have one of them:
1. i7-4770 3.4 GHz (this is mine) - the lowest tier one, even though it is a beast of a CPU.
2. i7-4770k 3.5 GHz (OC'd) - can be overclocked up to 4. something GHz.
3. i7-5930k 3.7 GHZ (OC'd) - the most beast CPU intel has released yet. Built for running any game smooth and sexy.
The prices are all dependent on the CPU of course, if you choose the highest tier one, it will most likely cost a lot of money.