All GeForce 8 Graphics Cards to Gain PhysX Support

J. Dzhugashvili writes "Nvidia completed its acquisition of Ageia yesterday, and it has revealed exactly what it plans to do with the company's PhysX physics processing engine. Nvidia CEO Jen-Hsun Huang says Nvidia is working to add PhysX support to its GeForce 8 series graphics processors using its CUDA general-purpose GPU (GPGPU) application programming interface. PhysX support will be available to all GeForce 8 owners via a simple software download, allowing those users to accelerate games that use the PhysX API without the need for any extra hardware. (Older cards aren't CUDA-compatible and therefore won't gain PhysX support.) With Havok FX shelved, the move may finally popularize hardware-accelerated physics processing in games."

Comments

Nice! But...

[johannesg]

...what will be calculating my 3D images, if the GPU is already working on the physics? It is not like there is so much spare capacity left over in modern games anyway...

Re:Nice! But...

[eggnoglatte]

They're not the same as the main graphics processors; they're a separate part of the chip AFAIK. You know wrong. OpenGL, Direct 3D and CUDA all share the same stream processors on the chip.

(Think! Why would NVIDIA waste expensive chip real estate for stream processors if they weren't useful for 99.9% of the applications running on these chips?)

Re:Nice! But...

[volsung]

On the CUDA forums, we've gone back and forth about this, and the diagrams that people base this statement on are backwards. There are 16 multiprocessors (to use the NVIDIA terminology), each with 8 stream processors per multiprocessor. The 8 stream processors on each multiprocessor run the same instruction at once, but on separate register files. Multiprocessors, however, are completely independent, so in principle, one could imagine partitioning the resources between physics simulation and 3D rendering. This sort of partitioning has not been made available through CUDA yet, but hopefully this means we will see it soon.

You are correct that these 128 stream processors (however you slice them) are the main compute engine. There is additional circuitry to do hardware accelerated video decoding, but NVIDIA has not exposed that functionality to 3rd party programmers, and it isn't used during 3D rendering.

Re:It's the "Ray" experience.

[tolomea]

Better is very subjective. We have both nVidia and ATI based thinkpad laptops running Ubuntu at work. And what I've noticed is that the ATI ones can do a kernel update with out screwing up the gfx drivers and they can switch between single and dual monitors (necessary when going on and off dock) without restarting X. On the other hand the nVidia ones have a pretty lil graphical config tool, while the ATI ones use a somewhat arcane and unreliable command line program. Personally I wouldn't trade my ATI one for an nVidia one any day, I very much like being able to unplug from the dock and switch down to single screen without closing and restarting all my apps.

So, what's actually accelerated here?

[91degrees]

Physics covers a lot, from gravity, inertia, particles, collisions, IK and various other bits and pieces. Not everything lends itself to acceleration. So what will be accelerated by this?

Re:So, what's actually accelerated here?

[TeknoHog]

Obviously, gravity and other kinds of non-steady motion are good targets for acceleration. And because of NVidia's evil closed source drivers, the best way to accelerate your GeForce is at 9.81 m/s**2.

Re:So, what's actually accelerated here?

[vux984]

From what I understand of this (and I could be wrong), the physx accelerator is primarily used to add eye-candy -- so things like showers of sparks, sprays of blood, geysers and clouds of dirt or water or snow on an impact (whether a footfall or a weapon strike...), leaves falling when you shoot trees, better hair and clothing, clouds, rain drop impacts, etc, etc.

All the physics processing for all those particles can be offloaded to the physx engine, allowing more particle effects to be going on at higher level of detail and realism (e.g. incorporating 'wind' etc..) without dragging down the cpu.

Its cool... but not earthshattering. And its a logical step to incorporate it into a video card.

I don't honestly know if it it can really be used to assist with the trajectory calculations of the interactive players tank or fighter plane or whatever, etc... but I doubt it. And it probably doesn't matter either. That is a minor part of the scene...each shower of sparks by itself probably requires more physics calculations than an entire squadron of planes... more independant particles in the shower.

Re:So, what's actually accelerated here?

[teslar]

Naw, it's much easier than you think. All of Physics can be expressed by just one equation, the Grand Unified Theory, the computation of which is accelerated by PhysX. The Grand Unified Theory was first discovered when programmers at Valve tried to optimise the physics engine of HL2. From the link:

Game Engine Software Engineer at Valve, Jose Garcia discovered the theory. "The game engine ran too slowly. I was assigned the job of speeding it up," he said. "I started out by combining some of the gravity equations with some of the other force equations and found it all started to fit together. After a day, I had fine-tuned the entire physics-animation functions down to four lines of code, which ran a bit faster," he added.

;)

Re:So, what's actually accelerated here?

[cnettel]

I don't think that's the case. Graphics cards work on the same PCI-X buses that acceleration cards probably use lately. They use DMA to communicate with main memory without involving the processor. The VRAM might be optimised for writing, but it should be very possible to do calculations on the card, and get the results back. That's the whole point of the generalised GPGPU techniques.
Nitpicking: PCI Express is not PCI-X. PCI-X was a derivative of the parallel PCI bus and never found in mainstream machines.

Re:It's the "Ray" experience.

[BiggerIsBetter]

Whereas for me, ATI hasn't had usable XV support since 8.35.5 (or thereabouts), and the 3D rendering is buggy as hell... which kinda defeats the purpose of using a dedicated GPU. Go look at the known issues in the release notes - it reads like an alpha dev-snapshot. I regret fitting ATI to my laptop for the sake of a supposed performance advantage over the Nvidia option, and my next machines will absolutely be NVidia Quadro (Sun workstation, yes Nvidia even provides drivers for Solaris x86) or Intel integrated (ultraportable notebook).

Re:Open Source != Holy Grail

[pinkocommie]

Not quite true. They said they'd release the specs so said driver could be created but they only released partial specs for the 2D aspects of their chips. They still haven't released updated doc's for 3D/Video rendering etc

Re:It's the "Ray" experience.

[mdarksbane]

As an OpenGL developer, I can say that I will never touch an ATI product when I have a choice.

Their driver support lags behind nVidia by years, and when they "support" a feature, it will often be in software with no warning that it is - so instead of failing with a useful error message, all you know is that *something* you did causes your system to render at 1 frame per minute and be completely unusable.

I have spent weeks bending over backwards and through hoops to get our ATI test card to agree with me, just because it is so darn unresponsive when anything goes wrong. Non power of two texture in one of your models because the modeller apparently ignored your instructions? No warning, no error - just a hung machine that will take 5 minutes to kill the process.

Give me nVidia any day.