Nvidia Denies Accusations of Disabling Multi-Core CPU Support in PhysX API

Nvidia: AMD’s Accusations Completely False, PhysX Takes Advantage of Multi-Core CPUs

by Anton Shilov
01/21/2010 | 05:39 AM

Nvidia Corp. said that it had not disabled support of multi-core central processing units (CPUs) in its PhysX application programming interface (API) and that allegations made by Advanced Micro Devices were not true.


“This is yet another completely unsubstantiated accusation made by an employee of one of our competitors.  I am writing here to address it directly and call it for what it is, completely false.  Nvidia PhysX fully supports multi-core CPUs and multithreaded applications, period.  Our developer tools allow developers to design their use of PhysX in PC games to take full advantage of multi-core CPUs and to fully use the multithreaded capabilities,” said Nadeem Mohammed, director of PhysX product management at Nvidia.

Mr. Mohammed used to work on PhysX at Ageia and then Nvidia, thus, he is a person that is more than familiar with the physics effects processing technology. According to Mr. Mohammed, since the merger with Nvidia there had been no changes to the software development kit (SDK) code “which purposely reduced the software performance of PhysX or its use of CPU multi-cores”.

In fact, according to the representative from Nvidia, it is technically impossible for the API developer to disable support for execution on certain amount of CPU cores.

“Our PhysX SDK API is designed such that thread control is done explicitly by the application developer, not by the SDK functions themselves. One of the best examples is 3DMarkVantage which can use 12 threads while running in software-only PhysX. This can easily be tested by anyone with a multi-core CPU system and a PhysX-capable GeForce GPU. This level of multi-core support and programming methodology has not changed since day one. And to anticipate another ridiculous claim, it would be nonsense to say we “tuned” PhysX multi-core support for this case,” said Mr. Mohammed.

Last week Richard Huddy, a software developer relationship manager at AMD, accused Nvidia of tweaking PhysX API so that processing of physics effects is only done on two microprocessor cores in order to artifically make graphics processing units seem better solution for computing of physics effects in games that use PhysX. Back in 2009 Nvidia disabled support of PhysX on the company's own GeForce GPUs as well as Ageia PhysX physics processing cards when drivers detected ATI Radeon hardware present.