AMD accuses Nvidia of disabling multi-core CPU support in PhysX API -- Nvidia says it's untrue.
Earlier this month, AMD worldwide developer relations manager Richard Huddy said in an interview with Bit-tech that Nvidia is squandering away CPU resources.
"The other thing is that all these CPU cores we have are underutilised and I'm going to take another pop at Nvidia here. When they bought Ageia, they had a fairly respectable multicore implementation of PhysX. If you look at it now it basically runs predominantly on one, or at most, two cores," said Huddy. "It's the same thing as Intel's old compiler tricks that it used to do; Nvidia simply takes out all the multicore optimisations in PhysX. In fact, if coded well, the CPU can tackle most of the physics situations presented to it."
We asked Nvidia for its response to the allegations made by AMD, Nadeem Mohammad, PhysX director of product management, stepped up to the mic in hopes of setting the record straight:
I have been a member of the PhysX team, first with AEGIA, and then with Nvidia, and I can honestly say that since the merger with Nvidia there have been no changes to the SDK code which purposely reduces the software performance of PhysX or its use of CPU multi-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.
PhysX is a cross platform solution. Our SDKs and tools are available for the Wii, PS3, Xbox 360, the PC and even the iPhone through one of our partners. We continue to invest substantial resources into improving PhysX support on ALL platforms--not just for those supporting GPU acceleration.
As is par for the course, 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.