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PhysX is a proprietary realtime physics engine middleware SDK originally developed by Ageia (acquired by Nvidia in February 2008) as the NovodeX SDK. Games supporting hardware acceleration by PhysX can be accelerated by either a PhysX PPU or a CUDA-enabled GeForce GPU, thus offloading physics calculations from the CPU, allowing it to perform other tasks instead - potentially resulting in a smoother gaming experience.

The PhysX engine and SDK are available for the following:

• Windows
• Linux (32-bit)
• Nintendo Wii
• Microsoft Xbox 360
• Sony PlayStation 3

Nvidia provides both the engine and SDK for free to Windows and Linux users and developers. The PlayStation 3 SDK is also freely available due to Sony's blanket purchase agreement.