I Cant find that file? "C:\Users\<Name>\AppData\Local\Arma 3 Alpha\"

my pc specs are:-

I7 3930K 3.2Ghz
16GB DDR3 1600 MHZ ripjaw
ati radeon HD7970 3GB DDR5

There should be no reason for frame rate reduction, as the game ran smoothly it was only the firing that was the issue, the movement and everybody ran around fine no jerking etc.

I will try and find this file and the dxdiag for you though.