but you probably won't be able to use PhysX (which is basically useless in this game anyway as it only applies to a smoke effect that is not terribly noticeable and kills performance).
After the latest patch, it appears PhysX performance has improved. I can now run it with no performance decrease in towns. There are also four PhysX settings where there used to be three.
I'm using a dedicated card though. I wouldn't run PhysX on a rendering card in this game..