Playing Demos on PhysX
Even though we can't benchmark CellFactor or Hangar of Doom in any useful way, they can't be left out when talking about the usefulness of PhysX hardware. It is very clear that using the AGEIA PhysX technology in a game can yield some impressive results. It is just as clear that current production games, while adding compelling visual effects, suffer a performance penalty that is difficult to justify.What we don't know is just how much more physics a PhysX card and do than the CPU or GPU already in every computer. We just haven't found a real world scenario in which to test the same large physics load on both the CPU and the PPU. None of the games that support PhysX include the ability to enable advanced physics features in the absence of hardware. The one small demo we do have that can run in either hardware or software mode does show a good improvement with hardware, but this test diagnostic app isn't designed as a performance analysis tool (nor is it a real world example of anything).
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Now that the CellFactor demo is downloadable, there is a little more value in picking up the hardware. Even though there is only one level to play with, the CellFactor demo is quite enjoyable in a multiplayer situation. It's not $300 USD worth of goodness, but it is a step in the right direction. It is rather impressive on a technical level, but with the full version of the game nowhere near release, the success of PhysX can't rely on CellFactor. We have a short video (3.7MB) available, although you might prefer the 400 MB video available on the CellFactor web site.
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Hangar of Doom is a demo based on Epic's UnrealEngine 3. This engine will power Unreal Tournament 2007, as well as a whole host of other games. Currently, UT2007 won't be requiring the PhysX hardware, but that shouldn't stop licensees from being able to take full advantage of it. While this demo isn't as complex as CellFactor, it demonstrates some neat ideas about the destructibility of objects in a game (planes fall apart when shot down). Again, we have a short video (2.1MB) available for download.
If you would like to try grabbing all six videos (13MB including the two from the original PhysX article) using a BitTorrent client, you may find that to be a faster solution (depending on how many people are seeding the files). Just download the torrent file if you're interested.
Unfortunately, even though these demos are very interesting and compelling, developers are not targeting levels of interactivity on this scale for the near future. With the current multiplayer trend, it doesn't make sense for developers to allow gameplay to rely on hardware that many users won't have. It isn't possible to have different gameplay in multiplayer environments. Effects are a different story, and thus the first games to support PhysX do have a tacked on feel to them.
Truly innovative uses of the AGEIA's technology are out there, but we are stuck with a chicken and egg problem. Publishers don't want to require the hardware until a large install base exists, and end users won't buy the hardware until a good number of titles support it.
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AndreasM - Wednesday, May 17, 2006 - link
In http://www.xtremesystems.org/forums/showthread.php...">some cases the PPU does increase performance. The next version of Ageia's SDK (ETA July) is supposed to support all physics effects in software, ATM liquid and cloth effects are hardware only; which is why some games like Cellfactor can't really run in software mode properly (yet). Hopefully Immersion releases a new version of their demo with official software support after Ageia releases their 2.4 SDK.UberL33tJarad - Wednesday, May 17, 2006 - link
How come there's never a direct comparison between CPU and PPU using the same physics? Making the PPU do 3x the work and not losing 3x performance doesn't seem so bad. It puts the card in a bad light because 90% of the people who will read this article will skip the text and go straight for the graphs. I know it can't be done in GRAW without different sets of physics (Havok for everything then Ageia for explosions) why not use the same Max Physics Debris Count?Genx87 - Wednesday, May 17, 2006 - link
I am still in contention it is a GPU limitation of having to render the higher amount of objects.One way to test this is to setup identical systems but one with SLI and the other with a single GPU.
1. Test the difference between the two systems without physics applied so we get an idea of how much the game scales.
2. Then test using identical setups using hardware physics and note if we see any difference. My theory is the amount of objects that need to be rendered is killing the GPU's.
There is definately a bottleneck and it would be agreat if an article really tried to get to the bottom of it. Is it CPU, PPU or GPU? It doesnt appear that CPU is "that" big an issue as the difference between the FX57 and Opty 144 isnt that big.
UberL33tJarad - Wednesday, May 17, 2006 - link
Well that's why I would be very intersted if some benchmarks could come out of http://pp.kpnet.fi/andreasm/physx/">this demo. The low res and lack of effects and textures makes it a great example to test CPUvsPPU strain. One guy said he went from http://www.xtremesystems.org/forums/showpost.php?p..."><5fps to 20fps, which is phenomenal.You can run the test in software or hardware mode and has 3k objects interacting with each other.
Also, if you want to REALLY strain a system, try http://www.novodex.com/rocket/NovodexRocket_V1_1.e...">this demo. Some guy on XS tried a 3ghz Conroe and got <3fps.
DigitalFreak - Wednesday, May 17, 2006 - link
Good idea.maevinj - Wednesday, May 17, 2006 - link
"then it is defeating its won purpose"should be one
JarredWalton - Wednesday, May 17, 2006 - link
Actually, I think it was supposed to be "own", but I reworded it anyway. Thanks.Nighteye2 - Wednesday, May 17, 2006 - link
2 things:I'd like to see a comparison done with equal level of physics, even if it's the low level of physics. Such a comparison could be informative about the bottlenecks. In CoV you can set the number of particles - do tests at 200 and 400 without the physx card, and tests at 400, 800 and 1500 with the physx card. Show how the physics scale with and without the physx card.
Secondly, do those slowdowns also occur in Cellfactor and UT2007 when objects are created? It seems to me like the slowdown is caused by suddenly having to route part of the data over the PPU, instead of using the PPU for object locations all the time.
DerekWilson - Wednesday, May 17, 2006 - link
The real issue here is that the type of debris is different. Lowering number on the physx cards still gives me things like packing peanuts, while software never does.It is still an apples to oranges comparison. But I will play around with this.
darkdemyze - Wednesday, May 17, 2006 - link
Seems there is a lot of "theory" and "ideal advantages" surrounding this card.Just as the chicken-egg comparison states, it's going to be a tough battle for AGEIA to get this new product going with lack of support from developers. I seriuosly doubt many people, even the ones who have the money, will want a product they don't get anything out of besides a few extra boxes flying through the air or a couple of extra grenade shards coming out of the explosion when there is such a decrament in performance.
At any rate, seems like just one more hardware component to buy for gamers. Meh.