Dont quote me on this, but Havok and "physics" has been around since 2000.

I dont understand this obsession with physics that HAS TO run on GPU.
Remember HL2 gravity gun, various see-saw and floating barrel puzzles?
What about Crysis, destructible buildings, and the way vehicles tumble when punched.
And many games have had waving cloth for years.

Recall that GPU physics was already around on X1800XT. Also remember those physics PCIE cards for Ghost Recon2.

Long long ago, in galaxy far far away, games like Unreal Tournament supported D3D, OpenGL, Glide, Metal etc. Lots of games had speedups with 3DNow! or MMX or SSE. But, nVidia PhysX doesn't just make things faster, but in games like Mirror's Edge, adds more glass shards when glass breaks and waving banners/cloth. Well, you can certainly very easily do that on CPU (regardless of how slow, make it an option). I image some consumers feel shafted that they get incomplete game experience because of the video card choice they made years ago. If way back when 10 years ago, programmers could add support for multiple standards, why not today.

PhysX is dead. Nvidia is supporting OpenCL. Apple, Intel, MS and AMD also supporting OpenCL. Move along, move along..