Tweakguides for you:
http://www.realitygamer.org/index.php?option=com_content&view=article&id=186&Itemid=217
http://segmentnext.com/2013/09/16/arma-3-tweaks-guide-graphics-and-performance/
http://day0.com.au/forum/arma/638-arma-3-performance-tweaks-and-settings-guide
Haven't tried these changes so read user comments before you try. Used to edit ini files for all my old games, great way to customise the graphics and performance (some things kill your frame rate without much noticeable improvement in the graphics)
http://www.realitygamer.org/index.php?option=com_content&view=article&id=186&Itemid=217
http://segmentnext.com/2013/09/16/arma-3-tweaks-guide-graphics-and-performance/
http://day0.com.au/forum/arma/638-arma-3-performance-tweaks-and-settings-guide
Haven't tried these changes so read user comments before you try. Used to edit ini files for all my old games, great way to customise the graphics and performance (some things kill your frame rate without much noticeable improvement in the graphics)