Cell Factor

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This is supposed to be an ageia only game however a simple command line hack allows you to play the demo without a PhysX card. It looks great although its a real system hog.....I have an X2 and SLI 7900GTX and it never get above 25 FPS. Funny how the game looks no different with and without PhysX.....anyone here own a PPU?

steviec

Rey Juicy Mugger wrote:

This is supposed to be an ageia only game however a simple command line hack allows you to play the demo without a PhysX card. It looks great although its a real system hog.....I have an X2 and SLI 7900GTX and it never get above 25 FPS. Funny how the game looks no different with and without PhysX.....anyone here own a PPU?

Only getting 25 FPS on such a ridiculously high end system really underlines how badly it needs the physics card doesn't it?

Haven't heard much about it, the guy who writes CTRL-ALT-DEL was very positive about it, I'll be interested to see how it turns out cos personally I think physics are a far bigger deal than shinier graphics, the problem being that they're not naturally scaleable like graphics so it's almost an all or nothing situation for devs, it may take a while before these become commonplace.

Pugsley

steviec wrote:

it may take a while before these become commonplace.

Its only a matter of time before they become incorporated straight into your gfx card I'd say, not going to get one seperate unless its 2 years down the road and a lot of games start requiring them.

stevenmu

The ageia card isn't supposed to change how a game looks, it's supposed to look exactly the same.

vibe666

not quite true.

physx allows for much more detailed particle effects such as detail in debris in explosions and flame/smoke/water effects which are not possible with current GPU's.

OSiriS

But the game still has to make proper use of the physics processor. If the game looks the same with and without, then the game is lacking.

conzy

The game looks the eaxt same without it, it just puts the GPU under serious preassure.....

All current Physics are calculated by GPU.......

stevenmu

vibe666 wrote:

not quite true.

physx allows for much more detailed particle effects such as detail in debris in explosions and flame/smoke/water effects which are not possible with current GPU's.

Not really, that can all be done without physx, or any type or physics acceleration, physx cards just do it much quicker.

OSiriS wrote:

But the game still has to make proper use of the physics processor. If the game looks the same with and without, then the game is lacking.

That's not the case for something designed exclusivly to qork with physx cards. A PC without a card can display everything a PC with one can, it'll just run a lot slower.

conzymaher wrote:

All current Physics are calculated by GPU.......

CPU, all current physics are calculated by CPU.






In short, the way things work are as follows. Without a physics card, the CPU keeps track of where all in game objects are, by tracking each objects speed and position, and altering them according to gravity, collisions or other factors, the CPU can decide where each object will belong in the next frame rendered. Once it has decided the new positions of each object it sends all the info to the GPU which renders the scene and displays it on your screen. Now, if there's a lot of different objects to move around, and a lot of different effects to apply to them such as altering all their positions by gravity, altering some according to an explosion, altering others according to collisions etc, then the CPU can get bogged down calculating them all, leaving the GPU sitting around waiting for stuff to render, which means low frame rates.

With a physics card installed, the CPU can just send it all the objects in the scene which need effects applied to them and tell it what effects to apply to them, and it'll do all the work and return all the new object positions which the CPU can then send on to the GPU to render. The GPU stays fed with lots and lots of stuff to render therefore higher frame rates.

There is a small 'but' to this. In general since games which make use of physics cards will run quite slowly without one, most will be designed to scale down the levels of physics used when a card is not present, so in practice there may be less particle effects or interactive objects etc, but there's nothing about physics cards that inherently allows better graphics.

jesus_thats_gre

vibe666 wrote:

not quite true.

physx allows for much more detailed particle effects such as detail in debris in explosions and flame/smoke/water effects which are not possible with current GPU's.

The card allows the real element of these particles but the GPU must still render the extra particles. The PPU takes the load off the CPU when physics calculations are being carried out but technically puts more load on the GPU if the physics calculations are just been used to create more detailed and realistic graphics.

Dooom

PhysX cards=ghey tbh.

I'm hanging on too see some more benchies from ATI's offering, then I'll start considering it.

conzy

CPU, all current physics are calculated by CPU.

I thought the CPU just acts as the middle man? Arent all the physics in games being calculated by the FPU units in the GFX card?

ShiverinEskimo

conzymaher wrote:

I thought the CPU just acts as the middle man? Arent all the physics in games being calculated by the FPU units in the GFX card?

It was my understanding that physics calculations are handled by the CPU. The GPU is purely for rendering. The CPU calculates vectors, speed, force - the mathmatical stuff before giving a map to the GPU for it to be rendered on screen. This is why running SLi 7900GTX with a P3 would be worse than running a GeForce4 with an FX60. The CPU quite often limits the performance of high-end cards. This is why a lot of people don't get the difference they expect when they upgrade graphics cards or go SLi - their CPU bottlenecks.

The Physics cards take away collision, particle and force calculations from the CPU allowing the CPU more resources to handle the user input, focus/nimbus, AI and other complex maths functions. The physics card reports back with its calculations to the CPU and then the CPU sends the info to the GPU for it to be drawn and rendered.

Someone please feel free to correct any of above. I'm no expert.

Cuddlesworth

ShiverinEskimo wrote:

The physics card reports back with its calculations to the CPU and then the CPU sends the info to the GPU for it to be drawn and rendered.

Everything you said is true, but this is the reason why people are not buying. Its dropping fps by loads because of this need to go from ppu to cpu to gfx. Untill they can place a ppu on the gfx cards or give it something like a hyper transport link.

gizmo

One thing to also bear in mind with the current crop of games is that activiating "PhysX mode" causes the game to actually render more objects on screen. The likes of GRAW does this rather noticably with far more particle effects present on screen when the PPU has been activated hence there is a frame rate drop becuase the GPU still has to render these new onscreen particles.

As for the GPU solution, meh Havok/nVidia and ATI are touting this alright but its rather insane if you ask me. Passing all of this onto the graphics GPU is going to severly cripple cards that are already being pushed to the max with the latest games so it remains to be seen whether performance benefits will be significant. ATI's idea is especially insane, "all you need" is three ATI boards running in Crossfire for an optimal solution. WTF like?

Microsofts DirectPhysics solution is also in development remember so thats definitly one to look out for. While Aegia is free for development studios once it passes the grandmother and gamer tests it still relies on having a PPU installed so while its going to get some great exposure with UT2K7 the take up rate is still going to be fairly low outside the upper end hardcore gamer segment.

Zombrex

ShiverinEskimo wrote:

It was my understanding that physics calculations are handled by the CPU. The GPU is purely for rendering.

The CPU is for anything you like, it is a general processor and can handle any task. In a modern game this would normal include everything else apart from graphics, from physics to things like user input. Originally 3D graphics were also worked out by the CPU.

The GPU is a chip specifically designed for working out 3D stuff, and contains its own bus and memory systems so it can work largely independently from the rest of the system, only needing to talk to the CPU when it needs something updated, like the 3D world changes.

But there is technically nothing to stop you from using that chip for anything you want, though it is not opitmised for general problems. Some physicals middleware companies have started to offer middle ware physics systems that can run on GPU cards.

ShiverinEskimo wrote:

The CPU calculates vectors, speed, force - the mathmatical stuff before giving a map to the GPU for it to be rendered on screen.

With the advent of GPU (nVidia GeForce 1 cards were the first for PCs) the graphics card can now work largely independently of the CPU and system memory. So while the GPU still taks to the CPU and system memory over the main bus, it doesn't need to do it so often as it did before, and large parts of the 3D environment can be held in the GPU memory. But you are right, the CPU obviously has to update the 3D environemtn held in the GPU memory based on user interactions.

ShiverinEskimo wrote:

The CPU quite often limits the performance of high-end cards. This is why a lot of people don't get the difference they expect when they upgrade graphics cards or go SLi - their CPU bottlenecks.

Not really, the reason SLi doesn't improve some games is because games have to be written to specifically support SLi. Just like having 2 CPUs in your PC will make no difference if the program you are running, or the OS itself doesn't know how to share the load of the program, running a 3D game that doesn't know how to share rendering between the two cards will mean the game doesn't run twice as fast.

ShiverinEskimo wrote:

The Physics cards take away collision, particle and force calculations from the CPU allowing the CPU more resources to handle the user input, focus/nimbus, AI and other complex maths functions. The physics card reports back with its calculations to the CPU and then the CPU sends the info to the GPU for it to be drawn and rendered.

Correct. Specialist processing units, such as the GPU or a Physics PU can be optimised and talored to the specific task they will always be carrying out, where as a CPU might be doing lots of different tasks. This means a GPU or PPU can be faster and more efficent at handling specific tasks.

The CPU still is in control, but if there is a dedicated chip for the more intensive tasks then it doesn't have to worry about them specifically, and is free to do other stuff.

Mad Mike

To be fair to Aegia there are subtle difference when running the game with and without a physics processor. See here http://blog.pcformat.co.uk/page/pcformat?entry=physx_a_sham
and here:
http://blog.pcformat.co.uk/page/pcformat?entry=uytu for more details.

In short the physics processor allows a waving flag to be done with realistic fabric effects and also allows a gooey liquid effect. The exploding boxes flying everywhere work just as well without a physics processor. The enhancements are far from earth shattering in my opinion and the whole affair is a PR disaster for Aegia.

Personally I hope the Aegia physics solution doesn't take off because I can't afford to add another expensive card to my PC. There is a competing solution from Havok which uses your graphics processor to do the maths. I hope the Havok solution becomes the de-facto standard because it will hurt our pockets less and because Havok is an Irish company.

According to this article http://www.reghardware.co.uk/2006/06/21/ms_directx_physics_programmer/
Microsoft want to include include physics in DX10 using the graphics card approach like Havok.

gizmo

Heh, you didn't even read my post did you.

Microsofts DirectPhysics solution was announced a good while ago and looks rather promising. Havoks solution, graphics card pressure aside, could be interesting but remember it will cost developers to include it in their software whereas MS' solution will be free, something that will play a significant role in the progress of each solution.

Not sure I agree with PC Format constantly calling it a "disaster" for Aegia. Sure the demo can be run without a PhysX card but for the really impressive visuals/physics objects to work at playable framerates you need one. Also remember that the Cell Factor demo only as a small level with one flag and if having it causes that much of a fps drop then you can see where Aegia are coming from...

Mad Mike

Faceless Man wrote:

Heh, you didn't even read my post did you.

Oops

I agree with you that Microsofts solution if they implement it is likely to become the Industry standard. Still wave a bit of a flag for Irish boys Havok though.

No sure I accept your argument about overloading the graphics card though. At the bleeding edge it makes sense to split out the functions to get the maxiumum performance but in the middle ground where most of us can afford to be it will be cheaper to buy a faster graphics card than to buy a seperate graphics card and physics card.

gizmo

Well it all depends on whether you value better graphics above better physics to be honest. Look at the likes of FEAR, Oblivion and Quake 4 et all. Once you start playing these games at high resolutions at Ultra levels of quality even top of the line hardware is going to be stressed. Now imagination what happens if the GPU now has to do phyiscs calcualtions aswell, somethings gotta give really.

It would be ideal of course if the user was given the choice of whether they wanted these additional physics effects at the cost of the overall game performance however since physics is such an integral part to the game engine is will be rather difficult if nigh on impossible to accomplish.