For me the poor perfomance seems to occur because of two things:

1. Everything in the direction I am looking seems to be rendering, even though I cannot actually see it. Looking into a wall inside a house in the direction of a city gives 20FPS. Looking into the other wall that is towards the sea gives 60-70FPS. This is very obvious when checking out the big new apartment buildings.

2. The GPU and CPU are not used fully. I realise that if one of them is a bottleneck the other may not be able to use 100%, but in all Arma games the usage of the CPU and GPU are both well under 100%. For me the GPU is around 70% and the CPU is around 60% in DayZ standalone.

My system:
AMD Phenom II X4 @ 3.4GHz
nVidia Geforce GTX660
16GB RAM + SSD.

Screenshot of CPU and GPU usage: https://dl.dropboxusercontent.com/u/699329/dayz_sa_cpu_gpu_usage.png
DXDIAG: https://dl.dropboxusercontent.com/u/699329/DxDiag_thebiffman.txt