How did you do that?
My specs:
Core i5 @3,6ghz
4GB corsair Dominator GT @1800mhz
Asus Maximus III gene
Radeon 5850
1Terabyte Samsung HD
everything on Medium except Texture quality (high)
View distance 2500m
Arma Mark 4300
but still low fps and some stuttering
Did you overclock your CPU?