I doubt you will get worse framerates with that. Metro 2033 is more demanding than Crysis. By the way what is your processor and how much ram do you have?
http://www.youtube.com/watch?v=hPl27AXSnuc&feature=related
at the end of this 1 they have a very undemanding battle as far as the battles go in metro... there in a confined dark space and you can see he's down to about 5 fps.
so no its not playable and it will be even worse when they went out side with more enemies.