I know Nvida has physics in its videocards, even tough not many games take advantage. Nevertheless, Im curious, Does Nvidia have a response for this? And do both nvidia and AMD offer physics in its mobile line of cards?
Assuming AMD does not offer a physics solutuion, is the physics CPU based then? Does it match Nvidias card?
Both companies have gpu calculated physics if the game is capable. This is because physx is not the only physics engine out there. Physx can be calculated on the cpu if nvidia is not present although usually with a big hit in fps. There are also tweaked drivers to have it work on amd cards or you can pair a nvidia card with amd.
Mobile or desktop is the same features. It's not a gimmick, there are games who partner with nvidia, and there are games who partner with amd. Physx without nvidia will be calculated by the cpu so amd gpus can't do physx officially but there are other physics engines that are gpgpu so run on any graphics card. True there aren't many games with physx because it would be smarter (larger consumer base) to have a game with physics that will run on any system. I could careless about physx on my nvidia card, it's not really important.
AFAIK the only true open sourced gpu accelerated physics engine is Bullet, which has been used to make movies. I might be wrong, but I think Disney's Cars used it.
The 3DMark 11 benchmark has PhysX, but purposely runs it off the CPU in order to test CPU performance. However, when it does the combined test, it runs the cloth physics using Direct Compute, which is available to both Nvidia and AMD.
In the end, the only thing Nvidia has over AMD for physics is PhysX acceleration.