The DirectX10 is better. In DirectX9 some of the trees are missing on the mountains in the first screen shot at the top of the page. In the third screen shot, the image for DirectX9 is blurry if you look closely (pay close attention to the left hand side of the shot when you make the comparison). Those who are still using XP will still be able to enjoy the game while as people using Vista are going to get the full utility from the game.