PhysX does not provide any help in rendering. Also you can't start PhysX programming as PhysX library is not open source like OpenCL and nVidia only shares the library with their authorized game developers.
So get HD6950 Twin Frozer III, best choice in rendering. You will also be benefited from the 2 GB frame buffer of it while rendering very intensive 3D models.
Please use google first before saying something so confidently:
PhysX Downloads | NVIDIA Developer Zone
Its not open source(most open source softwares don't advance fast enough, no offense), but its totally free, for both personal as commercial use.
Also note, amd's drivers related to rendering etc are a total mess, nvidia's drivers are more compatible and are better maintained, if rendering is your game
then get nVidia, nVidia still leads the market when it comes to workstation cards.
I have most of it figured out(thanks to you guys ) , just the card and the monitor i gotta decide on .
Now HD 6950 TF III PE 's APP or GTX 560 ti Hawk 's CUDA and Physx ? Which of these are better for rendering and stuff ?
Also monitor - Benq or Dell - any suggestions ?
Pure rendering? Maya. 3dsmax etc? Go nVidia eyes shut, try to grab a workstation card, casual renderer? Get nVidia but go with consumer cards, like 560ti.