This is possibly related to ticket 0000716. Arma3 is simply not utilizing all the resources availaibe.

I can confirm this occuring both online/offline. My CPU is only utilized around 40-50%, while my GPU is barely registering 20% use with lowest graphics and with ultra only 40-50%. Infact Ultra seems to run slightly better, but as its not fully utilizing the hardware its hard to tell.

Tried with full settings and with low settings but still get the same frames per second through out any setting. Cycled through many settings.

i7 920 @ 2.6 OC 2.8
4 GB Ram
Nvidia GTX 670 factory OC, Drivers 314.07
ran on a SDD Hard Drive

Tried the Nvidia Beta drivers 314.14, Seemed to mitigate the issue, as 70% use was maximum my gfx card went into processing the game. and easilly got over 35 fps with Very High at Ultra Post processing/AA and full HD