How PhysX runs on Nvidia and AMD (ATI) systems

[Goku]

I have been reading through these forums for hours upon hours, since PlanetSide 2 was formerly and I have been noticing many misconceptions regarding PhysX. Most of the misconceptions is in regards to how PhysX runs on Nvidia and AMD (ATI) systems. The purpose of this thread is to clear up these misconceptions entirely. I know there is threads floating around with information pertaining to PhysX use, but all of that info is scattered and has useless bickering.

PhysX software was originally introduced by Ageia and ran on a PPU (no longer exists) or CPU. Nvidia bought out Ageia in order to make use of PhysX themselves. With the Nvidia buyout you had more developers taking advantage of PhysX and this allowed Nvidia to put the software on their GPUs. A comparable Physics engine is Havoc that is only used on the CPU and in known for being used in the Source engine (HL2, L4D, and TF2).

There is two basic kinds of PhysX. First there is one for Physics that just uses CPU and has no attachment to using the GPU this being the more commonly used one. Second is accelerated GPU PhysX meant for specific types of Physics and this is the less used version being only in under 30 games.

No idea on what kind of PhysX PS2 is going to be using.

How accelerated GPU PhysX runs on hardware is different when running systems with either Nvidia or AMD GPUs. With Nvidia you can run PhysX on the GPU or CPU. On AMD you can only run PhysX on the CPU. There is no way to run PhysX on a AMD GPU.

Unfortunately there is a performance gap between running accelerated GPU PhysX on a GPU vs CPU. Running PhysX on a GPU allows for significantly higher performance then a CPU. If you have an AMD GPU you are going to be suffering a performance loss as result. Though there is a work around for this issue if you have an AMD card. You can get a hacked PhysX driver allowing for a Nvidia card to be used as dedicated card for handling the physics calculations. You can do this normally with a Nvidia card as well to get even higher performance then just making one GPU render and do physics calculations.

Here is a comparison from a review site:




This review used a 980X as the CPU. Even though the 5870 is a stronger card then this weaker version of the GTX 460 by running PhysX on the GPU it gets 2.5 times higher performance with PhysX on high. The 980X is the most powerful desktop processor out now and even that cannot out do PhysX being used on a GPU.



This here shows the GTX 275 being use as a dedicated card for PhysX calculations. You can see the the 5870 with the GTX 275 pairing allowed for a 2.5 times increase in performance with performance being nearly the same as the GTX 460.

What can we gather from all this? Like I mentioned before PhysX at the moment is nearly unable on the CPU. A Nvidia card must be used in someway in order to get proper performance if wanting to use PhysX. Be it using Nvidia as your primary card or having an AMD one plus having a Nvidia card for dedicated PhysX processing.

This is what the current accelerated GPU PhysX looks like. Nvidia is just recently released PhysX 3.0 to developers last month. I do not know if PS2 is being developed with this version. The new version promises greater performance on the CPU, but there is no games using this yet. With no games there is no to know the true performance yet in game with this new version when it comes to GPU vs CPU. There is NO mention of accelerated PhysX being used on AMD cards in this version. If it was it would of been mentioned, so for the time being do not think this version will allow it. Accelerated GPU PhysX still is a way for Nvidia to pull in more GPU sales instead of people going to AMD never forget that. Many developers use it as a way to get funds from Nvidia for helping develop the entire game like the TWIMTBP.

EDIT: Corrected the post as per feedback from Atranox's post.

[SwiftRanger]

Originally Posted by Goku

On AMD you can only run PhysX on the CPU. There is no way to run PhysX on a AMD GPU.

Odd, as SOE said otherwise multiple times during the video panels. They also said we could turn off PhysX completely though (compatibility with older rigs) so I don't think it's that important to PS2 as SOE/nVidia want to make us believe. Thx for the info though.

If it's really as "bad" as you say then this is major step backwards for the PC platform. These manufacturer-exclusive features can be neat but only if they're seen as an extra.

[Zulthus]

Originally Posted by SwiftRanger

They also said we could turn off PhysX completely though

I don't think they did. PhysX in PS2 will make bullet physics possible and give vehicles the ability to fishtail and such. I highly doubt it's togglable.

[RoninOni]

Originally Posted by SwiftRanger

Odd, as SOE said otherwise multiple times during the video panels. They also said we could turn off PhysX completely though (compatibility with older rigs) so I don't think it's that important to PS2 as SOE/nVidia want to make us believe. Thx for the info though.

If it's really as "bad" as you say then this is major step backwards for the PC platform. These manufacturer-exclusive features can be neat but only if they're seen as an extra.

You see the new Borderlands 2 vid?

Yah... you ain't gettin the full game unless you have nVidia... (the graphical difference is astounding)

so... yah, not buying.

I might upgrade in 18mo or w/e and they'll have a GotY on sale w/ all DLC by then :P

Originally Posted by CasualCat

I found it from the link in your signature.

This made me laugh

Originally Posted by JawsOfLife

Indeed. Doesn't get much clearer than that. Those with powerful Nvidia GPUs will have advanced physics performance and better visuals than those with AMD cards, it's that simple.

Actually, the "Enhanced physics" will likely put more particles on your screen ( a LOT more and yes, it WILL look awesome) which actually hinders your view more than someone with less or even physX disabled.

THAT'S the funniest part

Still, I'd rather have all dem particles

I'll live. (literally )

Seriously tho, I'm gonna need to upgrade :\

[MaxDamage]

How many times does this have to be stated?

YOU GAIN NO ADVANTAGES FROM OWNING AN NVIDIA GPU IN PLANETSIDE 2 WITH THIS PARTICULAR IMPLEMENTATION OF PHYSX.

IT IS CPU SPECIFIC AND NOT RELATED TO THE ENTIRELY SEPERATE BUT SIMILARLY NAMED GPU PHYSX FEATURE NVIDIA SUPPORTS IN A TINY NUMBER OF GAMES.

It has been falsely stated on some pages (geforce related) and speculated upon many times.

It is precisely this confusion that Nvidia hoped to generate.

[OnexBigxHebrew]

Originally Posted by MaxDamage

How many times does this have to be stated?

YOU GAIN NO ADVANTAGES FROM OWNING AN NVIDIA GPU IN PLANETSIDE 2 WITH THIS PARTICULAR IMPLEMENTATION OF PHYSX.

IT IS CPU SPECIFIC AND NOT RELATED TO THE ENTIRELY SEPERATE BUT SIMILARLY NAMED GPU PHYSX FEATURE NVIDIA SUPPORTS IN A TINY NUMBER OF GAMES.

It has been falsely stated on some pages (geforce related) and speculated upon many times.

It is precisely this confusion that Nvidia hoped to generate.

Chill?

[JawsOfLife]

Originally Posted by MaxDamage

How many times does this have to be stated?

YOU GAIN NO ADVANTAGES FROM OWNING AN NVIDIA GPU IN PLANETSIDE 2 WITH THIS PARTICULAR IMPLEMENTATION OF PHYSX.

IT IS CPU SPECIFIC AND NOT RELATED TO THE ENTIRELY SEPERATE BUT SIMILARLY NAMED GPU PHYSX FEATURE NVIDIA SUPPORTS IN A TINY NUMBER OF GAMES.

It has been falsely stated on some pages (geforce related) and speculated upon many times.

It is precisely this confusion that Nvidia hoped to generate.

So you're telling me that Nvidia "falsely" indicated that the Physx would be graphics-side, after it clearly says on their website, and I quote:

"The long-awaited, free-to-play massively multiplayer online first-person shooter, Planetside 2, is nearly here and sports advanced graphics, GPU-accelerated PhysX effects, and NVIDIA 3D Vision support to draw players into the action like never before."?

How do you know that they are wrong? And why would they purposely post false info?

[Toppopia]

As long as this runs on my Nvidea GeForce GT 230M card, then we can all stop arguing

Oh wait, i missed the point of the argument, oh well. I hope the programmers for Planetside 2 make this game as compatible as possible on low end systems. I wouldn't mind a low draw distance of maybe 500 metres, is anyone gonna be shooting me at that range? Probably, will they hit me? Definitely not.

[Zulthus]

I'm pretty sure it doesn't matter if you have ATI or Nvidia for PS2, since they most likely aren't designing PS2 with Nvidia users in mind. Metro 2033 uses PhysX heavily and I'm able to run it on my CPU with better than average performance on max settings. I haven't played/seen Mafia II, so I wouldn't know how graphics intensive it is.

[Sunrock]

Originally Posted by Zulthus

I'm pretty sure it doesn't matter if you have ATI or Nvidia for PS2, since they most likely aren't designing PS2 with Nvidia users in mind. Metro 2033 uses PhysX heavily and I'm able to run it on my CPU with better than average performance on max settings. I haven't played/seen Mafia II, so I wouldn't know how graphics intensive it is.

Mafia 2 is less graphic intensive then Batman Arkham City or BF3 for an example but, for being a 2 year old game it was very graphic intensive.

However my experience is that ATI cards run better in windowed mode then Nvida and Nvida runs better in full screen then ATI.

[Rbstr]

It depends on the kind of implementation.

You can have physx for some things, like vehicle mechanics and the like, always active. Then the physx for effects rather than mechanics be togglable.

[Hamma]

Very well put together thread thanks Goku

[Goku]

What SOE was saying I believe is that even if you have an AMD card you can still use PhysX by using the CPU. No other way around this issue at the moment.

Last I heard though the Metro 2033 did make use of PhysX to a good extant compared to previous games. I know Metro is considered among many to the Crysis of DX11 in terms of graphics too. If people find it playable all the power to them of course.

Like I mentioned though PhysX 3.0 is going to be taking more advantage of CPU power.



Again this is from the review. It shows the Core i7 980X in terms of scaling with a number of cores. Going to 1 to 2 cores there is a bump in performance, but after that even with 6 cores you have the same performance. If we are lead to believe PhysX 3.0 allows for more multithreading we could potentially at least 2 times the performance of PhysX on quad cores or higher. Going with that it would be smart to even have a quad core for this game if you do not have a Nvidia card.

Even if PS2 doesn't let you turn PhysX off, there maybe a low setting for CPUs to have to better handle the game. Nvidia wanted PhysX for their GPUs to boost sales, so with that I am positive the GPU will still out do the CPU by a good margin.

[Goku]

You're welcome, Hamma. I will be keeping an eye on this PhysX 3.0 version if there is news on its use and update the OP as needed. I am hoping to see some benchmark from Nvidia showing the CPU improvements soon.

@Swift.

I missed your point on this being bad for PC platform. Many people consider PhysX to be a closed API like CUDA, since at the moment only Nvidia cards can really make use of it. Those people argue there is alternatives like Havok that supports BOTH Intel and AMD cpus even though its owned by Intel that can be used in games. Right now I am hoping this PhysX 3.0 turns the table on this and makes PhysX seems more open source if the CPU can perform at playable levels. Early last year there was a major stink between AMD and Nvidia about this very issue. Lets just say I saw a lot of a lot of threads that turned into everyone being trolls. I do not want this thread to become that as its just to inform those who do not know about it.

[artifice]

Nvidia sent Sony a check to gimp ATI cards.