Poll: PhysX for the PS3

[Strelok17]

It's inevitable. Sounds cool, but it will be hard to start for PS3 devs.

Seeing as Sony's already announced that they're using the Cell in the Playstation 4 (don't ask me for a link, I'm far too lazy), I doubt that too many developers wouldn't want to go ahead and hop on the Sony train. Go ahead and learn the Cell, and if Sony uses NVIDIA again, go ahead and get physics processing under their belts is a big plus, also, many already know how to use it from using it on the PC.

 

[KSarty]

This isn't that great of an idea. The video card is one of the weakest areas of the PS3 hardware, it only has 256mb of VRAM. You'd be better off leaving the physics calculations to the enormous processing power of the Cell. Besides, PhysX isn't all that great anyways. Do you know why nVidia owns the PhysX brand now? Because nobody bothered to buy a PPU from Ageia because its a marginal increase in performance if any.

Actually the Cell can do processes in tandem with the GPU unlike normal processors, so it will probably be doing the calculations.
Plus the Ram in the PS3 is actually: 256MB XDR Main RAM @3.2GHz & 256MB GDDR3 VRAM @700MHz, so it's plenty fast enough.
Considering all Physx is now intergrated into the 200 series, plus now all to do with the code, rather than the physics accelerator:
http://www.youtube.com/watch?v=jzPO0LzF1ac
http://www.youtube.com/watch?v=wPxVE7A6MR4&feature=related
Having used the Havoc engine in 3d software, the Physx engine is much, much more effiecent, giving great & ultra-realistic results with very little CPU demand.
Unfortunaly as Ageia now have their ass secured by Nvidia, it's harder to find the demo videos they had of games with/without it to compare, as they really showed the difference it makes.

What you said about RAM is exactly what I said, 256mb of VRAM. The GPU shouldn't be accessing system RAM while doing graphics or physics calculations. Also, if the Cell would be doing the processing with this new SDK, then what is the point? Currently the Cell is doing any physics calculations already. The GPU is still one of the weaker points in the PS3 hardware, I don't see the gain in adding to it's workload.

Because very few games use over 50% of the Cells power...The GPU most likely won't calculate the physics as it's nothing to do with rendering etc, movement should be/will be the task of the Cell. As a system which is known for being great at calculations (210GFlops, 1.8TFlop), the more calculations given to it, the better.
My point on the Ram was the clock speed of it as it uses both the VRAM and the XDR RAM. At a speed of 3.2GHz, that's faster than current DDR3 speeds by a lot, so RAM shoudln't be an issue.

Wait now I'm confused, you're saying the same thing I'm trying to say. If this new SDK is going to make PhysX usable by the Cell then I'm all for it. All I'm saying is that if they add the physics workload to the GPU than they will be taking a step backwards. I would honestly assume that nVidia would make the SDK work with their own GPU rather than the Cell. Even if what you are saying about the Cell being able to work with the GPU is true, it would be adding to the process. The CPU is what dumps graphics calculations off to the GPU in the first place. If it dumps physics calculations off to the GPU only for the GPU to then dump it back off to the CPU, then thats not very efficient. Basically my point is keep physics calculations on the Cell and don't even involve the GPU would be the best route for the PS3.

 

[KSarty]

Wait now I'm confused, you're saying the same thing I'm trying to say. If this new SDK is going to make PhysX usable by the Cell then I'm all for it. All I'm saying is that if they add the physics workload to the GPU than they will be taking a step backwards. I would honestly assume that nVidia would make the SDK work with their own GPU rather than the Cell. Even if what you are saying about the Cell being able to work with the GPU is true, it would be adding to the process. The CPU is what dumps graphics calculations off to the GPU in the first place. If it dumps physics calculations off to the GPU only for the GPU to then dump it back off to the CPU, then thats not very efficient. Basically my point is keep physics calculations on the Cell and don't even involve the GPU would be the best route for the PS3.

Well I can't be certain as I have not looked deeply into it, but from practice, I'm almost 100% sure that physics is not entirely done by the GPU. Hence why when rendering complex physics scenes in 3D software (Maya, 3DS Max), if you reduce the amount of substeps per scene (amount of times the physics calculations are done) the FPS increases, yet the scene can have bugger all textures, lighting etc. The lack of anything graphically complex other than physics leads me to presume it's the CPU taking care of the physics, not the GPU.
Either way, I could be mistaken, but with more GPUs and CPUs being merged into whacky hybrid states (Cell BE with the RSX, the AMD FireStream etc) I think both parts would have to suck for the physics to cause an FPS slow down.

Generally, on any PC it is the CPU handling physics. The original Ageia cards were basically GPUs dedicated to physics, or PPUs. When nVidia acquired PhysX, they worked it into their standard GPUs to allow a GPU to do both physics and graphics, especially with SLI system. ATI has something similar but only for multi-GPU systems, you can allocate one of your GPUs to physics calculations through their catalyst control center. The reason I'm bringing all this up is because the original point of PhysX and similar products was to allow a powerful GPU that had excess usage available to take on part of the CPU's standard workload and increase overall performance. In the case of the PS3 however, the CPU is overwhelmingly powerful while the GPU would be considered mid-high range at this point. The standard convention of lightening the CPU's workload by giving it to the GPU shouldn't apply in this situation because of the power of the PS3's CPU and GPU respectively.

If their plan is to allow the Cell to use PhysX then it will work out great. If they want to take physics calculations away from the Cell and put them on the PS3's GPU through the use of PhysX, then I think you will only see a decrease in graphics performance as a result with little to no increase in physics performance. So depending on what route they are taking, I think this could be good or bad.

 

[shannon.archer]

yeah