MMGN.com: "As some Nvidia card owners may have noticed, enabling PhysX in a compatible game is quite taxing on a graphic cards performance. This is significantly noticeable when you have the other video settings set to higher settings. It’s not uncommon for people to disable PhysX effects, as it incurs effecting frame rate drops. To relieve the added strain PhysX has on your graphics card, a separate graphics card can be installed and dedicated to only PhysX calculations. Otherwise known as a dedicated PhysX card or PPU(Physics Processing Unit), by installing a dedicated PhysX card you will see PhysX compatible games run a lot smoother with no need to drop other graphic settings just to get playable frames per second."