For the last month or so I've issues with arma, after 1hour+ playing my fps drops to 3-5 fps, draw distance seems to drop to 20-25 meters, any players or ai nearby will only have gear visible (no player model) and one out of two things will happen.
1. The game recovers after 1-4 minutes and I can keep playing for a while.
2. The game stays at 3-5fps for 1-3minutes then black screens and the process hangs afterwards, having to kill the process through task manager.