Just thought i'd share a simple little tweak here to potentially increase framerates for some users.
I run crysis3 on a 670sli surround setup, However this also helped with single gpu 670
Very simple
Before you load the gamesave
Set System Spec to lowest
Load up your save
Now set System Spec : V.High
Postprocessing : High (for ADS DOF)
All done!
my results First checkpoint first mission(silencer on) without tweak 27~40ish 42~54 post tweak
Loading the game @highest sys spec then attempting the tweak will not work
You must load any mission @lowest then set to highest after its loaded.
This may not work on all systems or help at detail settings below medium SysSpec YMMV
Good luck