Information on Video Card support
Mafia II requires a GFX card that supports shaders 3.0 or later to run. The game will run with a nVidia GeForce 8600 / ATI HD2600 Pro or better.
Please note that the following cards are not supported:
ATI Radeon 3450
nVidia 8400 GS TC
nVidia 8400
For a more in depth look at the games other requirements please see here