is this computer good for dayz

Runs dayz, crysis, far cry, battlefield, and any other graphics dependent game. Seriously, I sure hope you are intending on running more than just dayz on your system, because if not it's a major overkill.

Also, just a heads up, I know what people might say that the gtx 970 requires at least a high quality 500w psu (I'm sorry but yours isn't going to qualify); I would recommend at least a 600W (or higher) bronze or gold PSU from a much better brand like Seasonic.