Has anyone had problems with Day Z? (standalone or mod)

Has anyone else with a good PC had problems with Dayz itself or the mod? ARMA games in general seem to be working bad. (by "good" PC I mean a PC that can definitely run the game, or more).
I don't have the standalone game, but I do have the mod on Steam and I havent been able to play it without problems.
It's like, it runs at huge FPS (100+), but if I move the mouse it drops below 10. Then if I change some things on the settings, I can make that disappear but then if I press something on the keyboard, it takes about half a second to make the action on the screen.
If I solve the keyboard delay problem, the first one appears again, and so on.
The computer cant really be the problem, since it's good, and I have seen people play the game with smaller computers.
Any comment?