I just bought ARMA2 on steam, have everything set to Very High.
Started up training, and the game is unplayable. It runs way too fast. I move around like the flash, with foot step noises going at a drum roll pace. I free look too fast as well, turning down mouse sensitivity all the way just makes it somewhat controllable.
My system is as follows
AMD p2 x4 3.6ghz
radeon 6850
win7 home x64