Yea, dayz is not a huge cpu hog, but a dual core i3 isn't going to cut it. Kind of funny you have a $750 graphics card with a $80-100 cpu. But yes, its the cpu. Don't go crazy on a i7, for gaming you'll rarely use more than 4 cores, get an i5 4760k instead. Also, no need for 16gb let alone vengeance pro, just get decent 1600mhz 8gb (2x4gb sticks). Motherboard, is a little overkill, but well suited towards gaming.
If you're going to get a Z97 board, why not get a Haswell-E chip to compliment it? Not that there's anything wrong with a 4670K, but in some places there's only ten or so dollars difference between it and the Haswell-E counterpart, 4690K.