What's going on is that the optional PhysX card in the M1730 is one made by Ageia before they were bought out by nVidia. nVidia has since changed the PhysX API to add new features that are supported by nVidia GPU drivers but not by Ageia PhysX PPUs. As a result, nVidia has discontinued support for Ageia PPUs in their PhysX drivers.
You now have a choice between installing really old nVidia PhysX drivers with Ageia PPU support but lacking newer PhysX features, or installing new nVidia PhysX drivers without Ageia PPU support.
In other words, your internal PhysX card is useless for newer PhysX games. I regret paying for the one that came with my M1730, as I've never even played any games on it that could take advantage of it. Oh well.