I think two components of your PC are slowing you down, either/or RAM and CPU. I think this because: DayZ is heavily CPU intensive, but not GPU intensive, I have a standard version of the same GPU, and get at least 40 fps in the middle of Cherno, in typically laggy situations (i.e. vehicle explosions, many zombies and players, artifacting etc.). I think 8GB of RAM is enough, but I play with 16GB, so I can't say for sure.