If the picture is blurry, it is caused by the 3D Resolution settings. This setting gives you the possibility to raise your FPS significantly. That however will negatively impact your picture quality, as it effectively lowers the resolution that the game is rendered in while still displaying the whole screen.
That causes the blurriness of the picture you see. If you want to have the picture as clear & crisp as possible, you have to set the 3D Resolution to 100%.
Check the picture below. What you can see is the 100% 3D Resolution, however if you go over the picture with your mouse cursor, you will see the effect of lowering the 3D Resolution to 50%. To compare both images in full size, you can also open the 100% version and the 50% version in full resolution.
Another way to lower the resolution and keep the crisp picture is to simply play the game in a window after lowering it.