Rarely does an issue divide the gaming community like PhysX has. We go deep into explaining CPU- and GPU-based PhysX processing, run PhysX with a Radeon card from AMD, and put some of today's most misleading headlines about PhysX under our microscope.
The history and development of game physics is often compared to that of the motion picture. The comparison might be a bit exaggerated and arrogant, but there’s some truth to it. As 3D graphics have evolved to almost photo-realistic levels, the lack of truly realistic and dynamic environments is becoming increasingly noticeable. The better the games look, the more jarring they seem from their lack of realistic animations and movements.

When comparing early VGA games with today's popular titles, it’s amazing how far we’ve come in 20 to 25 years. Instead of animated pixel sprites, we now measure graphics quality by looking at breathtaking natural occurrences like water, reflections, fog, smoke, and their movement and animation. Since all of these things are based on highly complex calculations, most game developers use so-called physics engines with prefabricated libraries containing, for example, character animations (ragdoll effects) or complex movements (vehicles, falling objects, water, and so on).
Of course, PhysX is not the only physics engine. Up until now, Havok has been used in many more games. But while both the 2008 edition Havok engine and the PhysX engine offer support for CPU-based physics calculations, PhysX is the only established platform in the game sector with support for faster GPU-based calculations as well.
This is where our current dilemma begins. There is only one official way to take advantage of PhysX (with Nvidia-based graphics cards) but two GPU manufacturers. This creates a potential for conflict, or at least enough for a bunch of press releases and headlines. Like the rest of the gaming community, we’re hoping that things pan out into open standards and sensible solutions. But as long as the gaming industry is stuck with the current situation, we simply have to make the most of what’s supported universally by publishers: CPU-based physics.
Preface
Why did we write this article? You might see warring news and articles on this topic, but we want to shine some light on the details of recent developments, especially for those without any knowledge of programming. Therefore, we will have to simplify and skip a few things. On the following pages, we’ll inquire whether and to what extent Nvidia is probably limiting PhysX CPU performance in favor of its own GPU-powered solutions, whether CPU-based PhysX is multi-thread-capable (which would make it competitive), and finally whether all physics calculations really can be implemented on GPU-based PhysX as easily and with as many benefits as Nvidia claims.
Additionally, we will describe how to enable a clever tweak that lets users with AMD graphics cards use Nvidia-based secondary boards as dedicated PhysX cards. We are interested in the best combination of different cards and what slots to use for each of them.

Everyone could be enjoying cpu based Physics, making use of their otherwise idle cores.
The problem is, nVidia doesn't want that. They have a proprietary solution which slows down their own cards, and AMD cards even more, making theirs seem better. On top of that, they throw money at games devs so they don't include better cpu physics.
Everybody loses except nVidia. This is not unusual behaviour for them, they are doing it with Tesellation now too - slowing down their own cards because it slows down AMD cards even more, when there is a better solution that doesn't hurt anybody.
They are a pure scumbag company.
Thank you, Tom's, thank you Igor Wallossek for makinng it easy!
You just made my day: a big thumbs up!
I've been running a hybrid system for almost half a year now. I have a 5770 (replacing it with a 6970, assuming it ever comes out while I still have money to my name) and GT 240 with 512 GDDR5. (I got it for 30 before tax on a whim) The only game I've ever found improved by the 240 is Mirror's Edge. I can get some pretty glass shattering while my friend's GTS 250 just craps out. However, a hybrid system does have the advantage of CUDA. Start up a CUDA app, boom, get awesome opengl (or directX) performance and cuda acceleration. One caveat with my 240 is that you need at least 768mb (I THINK) of vram to enable the Mercury Playback Engine is CS5.
Everyone could be enjoying cpu based Physics, making use of their otherwise idle cores.
The problem is, nVidia doesn't want that. They have a proprietary solution which slows down their own cards, and AMD cards even more, making theirs seem better. On top of that, they throw money at games devs so they don't include better cpu physics.
Everybody loses except nVidia. This is not unusual behaviour for them, they are doing it with Tesellation now too - slowing down their own cards because it slows down AMD cards even more, when there is a better solution that doesn't hurt anybody.
They are a pure scumbag company.
I always enjoy reading your hate it's like i'm reading Charlie except not quite as eloquent.
So would you rather have a game with 0 physics/really shitty or one that nvidia proved to the devs for free? Should i point out all the games that utter lack AA all together funny how such a basic thing can be overlooked, things cost money. The article points out a large portion of the bad cpu utilization is due to no dev work to make it better that cuts both ways not just to nvidia.
Nvidia is a publicly traded company any action that they make is made in the interest in profits anything else gets people fired.
It's cool how the article is about phsyx but you bring up tessellation and then end it with scumbag company. Maybe i should bring up how ATI cuts texture quality.
So why would nvidia who already is spending butt loads of money developing a game for another company cut down it's own bottom line? The stuff is all there it's just a matter of devs actually doing the leg work, which nvidia would be stupid to do themselves. With people like you they could cure cancer but still be satin, so you already are the case study to why they shouldn't do any real work do improving cpu utilization with their Phsyx, because i'm sure to you it would just fall on deaf ears.
Granted even i don't quite get the gambit of cutting ATI support for physics but business is business, and like all things proprietary the end users always loose.
Looks like you might be better leaving physx to the 8800s...
Heh why should nvidia spend their time and money to help AMD? It's as much nonsense as saying Toyota should help Ford be cause that too would be for the greater good. Yeah damn those scumbags at Toyota!
Other 99 don't bother at all and avoid phisix to get smoother gameplay.
Is it really worth it in eyes of Jen-Hsung?