Arma 2 is all CPU when in large cities. That 20fps would turn into 30-35 fps if you had an i7 at 4.2ghz.
 
oh wait you do have an i7 at 4.2ghz.... Hmmmm. Try disabling Post Process effects, that should give you a nice boost. It also clears up all the blurriness and makes the game look better imho. I have everything maxed out except for AA and Post Process is disabled. Sometimes I use AA on Normal or High and it doesnt really effect the 30 fps i get when im in cherno.

OV3RCLK4

Arma 2 is all CPU when in large cities. That 20fps would turn into 30-35 fps if you had an i7 at 4.2ghz.

 
According to his mods rigs, he has exactly that: an i7 (950) at 4.2 GHz.  Here are a few tips.
 
- Keep 3D resolution 1:1 with native resolution
- Keep view distance at 3500 or less
- Don't use MSAA or ATOC, use FXAA on whichever setting looks better to you
- Set VRAM to default
- Set terrain quality to normal
- Set HDR quality to normal
- Set post processing to normal
- Set object detail to normal
 
It takes at least a single GTX 600 series card or AMD 7900 series card to max out ArmA 2/OA at 1080p, though Day Z is even more demanding.  ArmA 2's SLI support is bad, which is one of the reasons your performance is lower than you expected.

OV3RCLK4

I get 60fps everywhere but the big cities where it dips into the high 30's. I have FXAA (Sharp Filter High) and AA on HIGH. Everything else is maxed to VERY HIGH except for Post Processing which I have disabled. 3D res is 1080p.

 
Is this Day Z or just regular ArmA 2?  Day Z runs quite a bit worse.  Otherwise I suspect ArmA 2 doesn't like his beta GPU driver.  Also do you run HT?

OV3RCLK4

I do not run HT atm.

 
^ This may also help (disabling it).  I can't confirm this though, not having a HT CPU.

Enad1

The latest beta drivers are 306, not 206, so might wanna update. 

He has 306.02. The 206.02 is obviously a typo.