ArmA 2: DayZ and DayZ Standalone are very CPU intensive games, so the problem is definitely your CPU. If you want to play DayZ with decent frames, think about upgrading your CPU. A newer Gen i5, or if you can afford it even an i7 should do it. If you dont want to spend too much money, or dont like Intel, go with the FX-8350from AMD, though i would prefer the i5 over the 8350. Hope i could help you a bit. Greetings -Gh0ST :)