I too am experiencing this problem. Arma II runs at over 60 FPS consistently but as soon as I boot up DayZ that gets cut in half. In DayZ I've changed the settings form the highest to the lowest settings, with only a slight change in FPS, indicating that there is something else at play here. My setup: AMD Phenom x6 Thuban @ 3.6 gHz 2x Radeon HD 6870 8gb Ram edit: 3.6