The main competitor of PhysX technology – and a much more established one at that – is the Havok SDK. This physics engine is used in many successful games including Half Life 2. It works by offloading physics effects to the GPU as Shader Model 3.0 instructions while sending gamplay physics instructions to the CPU. This obviously has it’s advantages in the fact that it is completely self contained and doesn’t need a seperate card to calculate physics, but it does mean extra CPU load and that the ammount of physics calculations that can be processed is limited to CPU power.
ATI and Nvidia have pledged to develope their own physics options. ATi have stated that they aim to a stream processor product which combines a CPU and GPU on one chip while Nvidia’s 8 series cards support a physics system called “Quantum Effects Technology” which is designed to directly compete with the PhysX PPU.
Ageia believes that by using a dedicated PPU game developers will have the option to use much more comlicated in-game physics and much more interaction between objects. They have recently showcased this in the much anticipated CellFactor Revolution where hundreds of objects can be seen displaying realistic physical traits through the way they interact with each other’s movements and the actions of the character.
NB. This was taken from my previous PhysX Review