PhysX Card with Crossfired AMD GPUs... and in the x1 PCI slot?

[wannaturnuptheheat]

I've heard that pretty low-end Nvidia GPUs can be used for PhysX and, provided you have a good main graphical setup, it works fine.

Is this at all reasonable, though? That is to say, not only is my system AMD/ATI (two 6870s), but I only have PCI x1 slots open. Will a PhysX card even work if I used one, and with PCI x1, would it even be effective?

 

[17seconds]

I'm guessing it will work, once you use the PhysX hack. Since it's not processing graphics, I think the x1 slot will be okay.