DayZ and similar open-map games are quite CPU intensive because of the rendering of the entire map. GPU is after CPU in these types of games usually, unlike other games such as most first person shooters. I would recommend getting a newer (Still not new, but newer... The socket-771-was released in '06.) socket 771 Xeon or a Core 2 Extreme (Although these cost a fortune, but you may be able to find one for cheap used). If you don't feel comfortable doing this, I would recommend picking up an AMD 970 chipset board (These are the cheaper chipsets) and an FX 6300 or 8320/50. AMD really prevails in multi-core work loads, and while it has 5% less single core performance than Intel, it has 5% more multi-core performance.
When/if you get the...