Tak (DayZ)

I would suggest trying a few different servers, I get a lot of lag just from certain servers. The only other thing that I can think of is that it may be your internet connection. There doesn't seem to be anything wrong with your specs, they are near enough equivalent to mine and my game runs without lag 95% of the time.

The only thing I can suggest is reinstall Operation Arrowhead and run it before you attempt to play Dayz again. If you've already done this or it doesn't work.... I'm out of ideas.

I had a similar problem, did you run both Arma2 and Operation Arrowhead before installing the mod? If not that may be your problem. To do this you may have to reinstall one (or both) of Arma and OA. I hope this helps you.