Nvidian denies hobbling multi-core PhysX

AMD Developer Relations boss Richard Huddy recently made some pretty damning accusations about arch rival Nvidia's PhysX systems, claiming the outfit had deliberately hobbled PhysX on mutli-core systems.

Now NV's Nadeem Mohammad has bitten back in the tit-for-tat mudsling that both companies traditionally indulge in.

Speaking to Bit Tech's Richard Swinburne, Huddy was reported to have said: "All of 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. That's pretty shabby!

"I wonder why Nvidia has done that? I wonder why Nvidia has failed to do all their QA on stuff they don't care about - making it run efficiently on CPU cores - because the company doesn't care about the consumer experience, it just cares about selling you more graphics cards by coding it so the GPU appears faster than the CPU."

On a roll now, Huddy added: "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. The emphasis we're seeing on GPU physics is an over-emphasis that comes from one company having GPU physics... promoting PhysX as if it's God's answer to all physics problems, when actually it's more a solution in search of problems."

We don't know where Huddy was educated, but we're pretty sure they won't have taught him that publicly calling your competitors 'shabby' and accusing them of not caring about their customers was acceptable behaviour in a polite society.

Nvidia's Nadeem Mohammad, on the other hand, is the very model of polite restraint. Mohammad has been at the very heart of PhysX development from some time, having moved over to the Green Side from Ageia.

He said in his official blog: "Recently, an interview ran with an AMD developer relations manager, who claimed that Nvidia (after acquiring Ageia) had purposely reduced the performance and scalability of Nvidia PhysX technology, with regards to CPU core utilisation.

"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."

Slipping into mud-slinging mode, Mohammed writes: "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.

"There is lot more I say on this topic; however, I really have to get back to my day job, which is working to help make gaming great for all users! And today that includes cracking open a new copy of Dark Void, the latest PhysX title, which incorporates some awesome particle weapon effects, an insane Disintegrator gun with fluid particles and a jetpack with physical smoke turbulence .

"I know, hard work, right? But someone has to do it!"