I am using an i5 @ 3.5 ghz and a gtx 960. My system has 8 gigs of ram. I suspect this may not be enough, but system requirements for beta have not yet been made clear as far as I know. I was running only DayZ at the time.
I have always experienced stutter in offline mode. It is very apparent. But I did not experience any stutter in the first stress test I participated in, which was stress test 10.