The CPU Gets Loaded by Nvidia PhysX

Nvidia has put a lot of effort into making the PhysX technology a top competitive one. Its GeForce 8, 9 and GTX 200 Series cards feature PhysX support, and the company has also released the drivers that are supposed to enable the physics on the graphics cards. The green company has tried to make the performance levels go really high on games with PhysX when a GeForce card is used, which means that it expects others to adopt its technology as well.

All CUDA-enabled cards can run PhysX if the shaders support the feature. The drivers are said to also give a performance boost, allowing PhysX applications to run faster. Nvidia said a few weeks ago that, since the physics would be handled by the GPU, the CPU would be available to use for other tasks. Recently made tests have showed that things are not as Nvidia claims, and that the CPU is used more when physics are enabled on a graphics card compared to the physics handled by a PPU.

The guys from news site Fudzilla say that they have performed a test with a particle fluid demo from Nvidia to see how a GeForce 8800GT card would perform against a PPU card from Ageia. The test revealed that the graphics performance of the GeForce card is twice as that of the Ageia card. This result is not surprising at all, since Nvidia claims that the performance is highly boosted when the PhysX are enabled on its cards.

The results showed that the Ageia card could only do about 15fps while the GeForce 8800GT went to an average of about 24fps. Thus, Nvidia's solution proves to be faster, yet, since all the aspects of the test should be noticed, things may not really be this way. The CPU usage shows a massive difference between the two, and might truly show how things are. While only 30 to 40 percent of the CPU was used by the Ageia card, the GeForce solution loaded the processor to 80 to 85 percent and even higher sometimes.

The processor showed lower usage when the demo was run on pure software mode, which means that it relies only on the CPU, thus being much slower. It also seems that the software mode produced the same amount of particles as the GeForce card with either the GeForce or Ageia option ticked in the drivers. Perhaps Nvidia is not as fair as it claims to be, and that the GPU does not handle all the PhysX calculations as the company said it would.