The game uses DirectX11. But it has a compatibility mode with DirectX10.1, althought you will not be able to use some graphical features. Generally, not suggested to play with a card that doesn't support DirectX11.
oh ok thanks, i play it sometimes on my 2010 mac book air (1.8ghz C2D+GeForce 320M) and i always have it on lowest settings with textures up, and sometimes i get 60fps