%USERPROFILE%\Documents\Arma 3 - Other Profiles\<user-id>\Saved\steam
Some suggested FOV values in radians for typical setups are:
Set Launch Options...
For AMD CPU users:
-noSplash -cpuCount=2 -high
-noSplash -cpuCount=4 -high
-noSplash -cpuCount=6 -high
-noSplash -cpuCount=8 -high
For Intel CPU users:
Seems to work for some users, others not.
You can also use --eon_force_display=x command line parameter on linux builds, where x is your monitor ID.
Under steam, set command line like this : %command% --eon_force_display=0
This issue is critical and all users with multi-core processors are suffering from it. The developers have yet to comment on this issue on the official bug tracking site.
This critical engine issue gives users a ~40% performance loss at all times, the reason is that the engine has what is called a Engine Limitation, in this case it means that only a few processing cores are being utilized and take big hits that might be the reason for game stutter as the CPU can't handle all the requests on high-end settings.