Strange Game Issue

So ive been playing alot of Dayz and Arma II and ive been getting about 15 fps on my computer with all the Arma 2 settings on the lowest whereas my brother who has the EXACT same computer is getting about 30-40fps on medium - high.


I tried changing the settings the same as his ingame but to no avail. I've defragged my Hard drive, ran numerous pc cleaners, verified game cache in steam, edited the config files but it hasn't improved.

Any help would be greatly appreciated.


Computer Specs:

Intel i5 3570k 3.4Ghz

Nvidia GTX 660 2GB

8GB DDR3 Ram