The laws of physics squashed into a tiddly bit of chippery

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Product: Ageia Physx card
Website: ageia.com
System Requirements:
A vacant PCI 2.0 slot or higher DirectX 9.0 graphics card
Price: Around £130

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THE FOLK AT AGEIA, whoever they are, took umbrage when we described its Physx card as weird. So they eventually sent us one to have a fiddle with. You can buy the card for around £130 and today is the day that you can download a game - Cellfactor Revolution - to play it with. But, first you might like to know what it is.

On the card is a chip that is designed to take care of some of the processing of 3D action in games. How it works is something like this: the graphics card (GPU) in your PC deals with all the images on screen. Its responsibility is to get all those polygons and stuff fired to your monitor. And, basically, the more advanced the card the better its supposed ability to render life-like scenes in which you run about with - normally - a big, fat gun.

Your processor won't be idle while all this is going on. It deals with what games developers like to call Artificial Intelligence (AI). This is less to do with pumping the polygons to your screen, rather it is a bit more telling the graphics chip which polygons go where. This means where you run with your silly great gun, what happens if you shoot an alien, a friend or the wall.

Now, this is where Ageia's Physx card comes in. The idea is that the card extends the AI of a game so that movement becomes more naturalistic. The card essentially deals with movement and interaction, and by interaction we largely mean what happens when objects collide.

So the card sits in a PCI 2.0 slot and acts as a co-processor. You don't need to wire it up to your graphics card or anything like that. You just plug it in and the bus takes care of the communications between CPU, GPU and the Physx card.

Communications between CPU and GPU are one-way. The CPU tells the GPU what to do and it does it. Communications between the Physx card and CPU are two-way which is why Ageia claims that graphics card companies can't do what it does without changing their designs fundamentally.

As we noted above, the Physx card comes into play to enhance motion or the collision of objects. This means that when you as, say, the character Bishop in Cellfactor use your mind-bending powers to shift a bunch of objects in your path, the Physx card will calculate how these objects will collide and bounce about as you move them.

As our guide informed us, the laws of physics are programmed into the card so that when an object whose properties are known - a steel ball say - bangs into another object - a tin can, say - then from the angle and speed of the collision the card will determine the likely trajectory of the two objects, post collision.

All the laws of Physics? Well, no. But certainly many of those relevant to the movement and relative motion of bouncing balls. And certain types of explosion, and lava, and bits of string, hand grenades, rocket-propelled grenades. You know the sort of thing. Along with hair and grass which, while similar, always look a bit dodgy on 3D games.

So how does it look? Well it looks sort of, you know, OK.

Listen, your correspondent is a jaded old hack. He long-since stopped getting the horn over the latest graphics cards and so his enthusiasm for Ageia's Physx card is maybe a bit more muted than the firm would like.

Cellfactor Revolution is the normal sort of 3D game set in some far-flung, or, hang on, "futuristic, industrial, war-torn atmosphere." You know the sort of thing. You run around shooting things or blowing things up, or get shot and blown up, and all very entertaining it is too.

And with an Ageia Phsyx card plugged into your hot gaming rig, there's bit more detail in the way things bounce, or explode or get shot. Does it look more realistic? Well, you'd hope so with all that hardware trying hard to made it so. Thing is, in a "futuristic, industrial, war-torn atmosphere," you can't really tell.

Performance-wise there is some advantage as some of the CPU jobs are taken over by the card and you'll probably get more frames per second - not that you'll notice because you probably get more than the eye can detect anyhow.

Still, it's an interesting product and quite an exciting departure, really. We plugged ours into an AMD machine running some fast dual-core Athlon 64 chippery and a Sapphire X1950 graphics card and the whole thing flew like billy-o.

It's about as realistic a rendered 3D experience as we've yet witnessed on a PC. And you can in fact turn off the Ageia effects to assess the difference. And there is some. Asked to evaluate this, you might suggest that it looks, say 15 per cent more realistic.

Is it therefore worth having? That, we're afraid, is what you'll have to decide. ?