Well that should be plenty of power to run Arma 3.
Run GeForce Experience and look for updated drivers.
Or try deleting the Arma3.cfg file as I mentioned above.
First thing you can do is make sure your graphics card driver is up to date.
Other than that you can try to delete Arma3.cfg in the Arma 3 folder in Documents. That will reset your settings and hopefully launch the game.
I had a similar issue with another DLC update and deleting Arma3.cfg...