The Technology that is PhysX

BFG’s AGEIA PhysX card is finally coming out to market, and we’ve had our sample going through the paces for a few days. Testing with Ghost Recon: Advanced Warfighter and a Cell Factor demo to see what kind of performance and features we get for our $250.


According to AGEIA and BFG, the future is finally here.  We have been discussing and analyzing the prospects of a dedicated physics processor for PC gaming since AGEIA’s first announcement of it before E3 last year.  Initially we had only a very high level view of what AGEIA hoped to accomplish with their hardware and software technologies, but as time went by we have learned more about it.  Today we are finally seeing the finished product. 

AGEIA PhysX Background

The business plan for AGEIA was to seed their software physics API, initially called Novodex but later renamed to PhysX, for free.  Appealing to many developers for the low, low price of free-ninety-nine, the PhysX engine has made its way into several game engines such as Unreal Engine 3, due out later this year.  While developers can use the software API to run the physics in the software, the API also allows the developer to use the PhysX hardware to create even more complex interactions.   By giving away the engine and promoting it to developers, AGEIA is trying to create a large software base that will lend itself well to PPU hardware sales.

Getting past the business side of things, we have learned a bit more about the PhysX hardware and software than we have written in previous articles.  If you haven’t already done so, I would strongly recommend you look back at our two previous AGEIA PhysX articles.  The first covers the high level aspects that AGEIA wants to accomplish with dedicated physics processing, while the second one covers in more detail the methodology that the PhysX technology uses to accomplish these goals. 

Technology Purpose

While the name for this concept might seem a bit grandiose, the ideas behind it are very logical and put some good ideological weight behind the PhysX chip. 

BFG's AGEIA PhysX PPU Action Accelerator Card Review - Graphics Cards 45

In this diagram AGEIA promotes that by adding a PPU into the mix with the CPU and GPU, they are essentially increasing the power that both other components effectively have and also pushes them beyond their limits. 

Since the PPU would take a large majority of the physics work off the CPU, the processor would be less bogged down and thus could address more cycles to feeding the GPU with data to crunch and keeping the game state in order. This should mean an automatic frame rate increase for any games that were significantly CPU bottlenecked before the introduction of a PPU. 

Also though, there are some aspects of the PhysX chip that increase work loads on both the CPU and GPU.  Imagine that you have a wall of a castle raining down on your filthy, peasant head in a 3D, physics enhanced Trogdor game.  Now, instead of having just 30 pieces falling as you might with a CPU-based physics engine, you now have 3000 pieces falling.  All the physics calculations are being done on the PPU but now the CPU has to deal with an additional 2970 objects that AI and must avoid or deal with.  In the same light, the GPU now has to worry about rendering many different objects with possibly even different textures on portions of the wall that have broken away in different styles. 

This will in turn (hopefully) push AMD and Intel as well as NVIDIA and ATI to find new ways to increase their computational power in order to continue to increase the realism of gaming titles.

Next Page – The BFG PhysX Card and Power Consumption

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