I'm glad I'm not the only one seeing poor performance after the update. I ran some Fraps tests before and after the update.
Video Settings: 1920x1080, Ultra preset, Vsync ON.
Arma 3 1.16 Showcase>Combined Arms
Frames, Time (ms), Min, Max, Avg
8860, 166109, 29, 64, 53.338
Arma 3 1.18 Showcase>Combined Arms
Frames, Time (ms), Min, Max, Avg
7387, 163239, 17, 63, 45.253
My system specs:
Intel 4770k @4.3Ghz
16GB RAM 1600
Geforce GTX 780ti
Crucial M4 SSD
Nvidia Driver: 335.23
I hope the devs are taking this seriously as this is extremely disappointing to get such bad performance after an update. It wouldn't be so bad if we could actually roll back to 1.16. Its not only just a drop of 10 fps for me but also plenty of stuttering, etc. as others have mentioned.
I've tried reinstalling the game from scatch, reinstalling my video drivers, installing nvidia beta drivers (337.50) and nothing has made it better.