PhysX Performance Update: City of Villains

Final Words

While we still think that on paper, the AGEIA's PhysX technology has promise, we find ourselves in a situation similar to where we were a few months ago with Ghost Recon and the City of Villains beta. On the positive side, AGEIA and Cryptic have fixed many of our earlier complaints about using PhysX hardware acceleration under City of Villains. The game no longer stutters, and installing a PhysX card doesn't immediately result in a drop in performance (though this has much to do with the new way of adjusting physics settings and other optimizations Cryptic has made in how the game handles large quantities of debris).

However, what AGEIA has failed to fix, and what ultimately ends up counting the most, is value. There's no question that a PhysX card will give better performance in City of Villains at the highest settings, and at times that difference can be pretty sizable. But as we found out, using a slightly lower quality physics mode will result in graphics similar to the highest mode where the PhysX card shines, but at performance levels nearly equal to the PhysX card just by using a dual-core CPU. When we're talking about adding a $250 PPU to a system that's already using a $1000 CPU and a $500 GPU, the PhysX card is a sensible way to boost performance by a good measure without spending all that much more. Under a tighter budget, that's a much harder thing to recommend.

For someone currently using a single-core CPU and working with a limited budget, an upgrade to a dual-core CPU is going to be superior to adding the PhysX card in City of Villains, and it's going to be much more useful in games and applications where the PhysX card can't be used. Similarly, someone with a slower dual-core CPU may not see gains as great going to a faster CPU as they would with a PhysX card, but unless the extra eye-candy and a few frames is what you desire, the faster CPU will still be more useful overall. Ultimately, since City of Villains is CPU limited, the PhysX card is only the best upgrade when a system's CPU performance can't be improved much; otherwise, the effect of the CPU holding back performance is just too great to ignore.

Eventually, we still must question the usefulness of a product like the PhysX card on a game like City of Villains. Physics processing is an embarrassingly parallel problem, the kind of problem that the hardware industry has gotten extremely good at solving first with video and GPUs, and now physics and PPUs. But this technology must be put to a better use if AGEIA wants to drive more adoption and influence an era of video games that can make a massive jump in the number of physics interactions used. Adding more particles to games like City of Villains -- and then only to certain segments of the game -- is really demeaning for the hardware; it's not changing gameplay and it's not something at which a PPU can universally excel versus other options such as additional CPU cores, even given the sheer advantage of hardware optimized for these calculations over a general-purpose processor.

We still believe that PPUs can influence and improve gaming, but it must be done in ways that make sense in improving gameplay, or at the very least improve things in ways not related to gameplay such that there's a clear benefit over the alternatives. City of Villains and similar games won't be able to sell the PPU (with the exceptions of wealthy die hard fans); that will have to come in the following years as games like CellFactor take root which implement the PPU in a more pervasive manner to create an undeniably more immersive experience.

If AGEIA could even promise a consistent 25% performance boost over software mode in several games, more people would be interested in the technology. The problem is, many games are completely GPU limited, so faster physics processing doesn't necessarily help. What we end up with is the classic chicken vs. egg problem: without a large installed base of PPUs, how many developers will even bother to try and take advantage of the technology, and without software that takes advantage of the technology, who will want to buy the hardware? ATI and NVIDIA are also working on trying to accelerate physics with their GPUs, and every gamer will already have that technology available. GPU-based physics calculations might not be a good solution in games that are already GPU limited, but faster processors and PPUs won't help such games either.