Hi,
after playing Arma 3 (King of the hill) for about 60 minutes, the framerate will significantly drop (1 - 2 fps). Furhtermore objects will disappear from the map.
The frame rate will go back up to a regular 60 after 2 to 3 minutes. However, it will reoccur after a few minutes.
If you keep the game running, it will eventually crash.
Cheers