graphics co-processor?

October 9, 2006 7:50 AM

Does anyone have, or have you seen a computer with a video co-processor installed? (Like the PhysX card by Ageia) Is it worth the extra $250?
posted by crunchland to computers & internet (10 comments total)

Do you mean a physics co-processor? Almost every machine these days has some kind of graphics processing unit.
posted by fake at 8:02 AM on October 9, 2006

I wouldn't call PhysX a video co-processor... it's a physics engine. Almost every video card, though, includes a video co-processor of varying quality and most games available now are not playable without one. Even back in 98/99 when software rendering was an option, the results were truly terrible.

Also, the PhysX card is supported by a very small number of games (ony 4 or 5 at the moment) although there are a few dozen new games that will support it, and some existing games which will add support for it via a patch. I would not expect any of these to be amazing.

I think in order for such a thing to make a huge difference, the game would need to *rely* on a physics processor in some way, making it crappy without one (just like software rendering is way crappy compared to GPU rendering). The point where this is feasible is the point where it becomes an option for motherboards or video cards with the expectation that many or most future systems will include it - otherwise game manufacturers are not going to take the risk.
posted by RustyBrooks at 8:03 AM on October 9, 2006

ATI and NVidia are working on Co-opting the market for physics accellerators by doing the processing on the GPU. My guess is that this will be the winning strategy in the long run.

If it were me, I'd save the money that would go to a physics coprocessor.
posted by Good Brain at 8:31 AM on October 9, 2006

It's my understanding that, at the moment, the overhead involved in transferring the data to the card, waiting for the result, and transferring it back results in lag... sometimes bad lag. The PPU can accelerate a lot more than the main CPU, but because of the inefficient data path over the slow PCI bus, the net result is a slow, choppy game with a billion more things being thrown about.

PCIe may be better. AMD also appears to be working on a way of plugging one of these chips into a special socket in their Hypertransport bus, which is how they glue multiple CPUs together.... this is very, very fast, and should fix lag problems from bandwidth starvation.

As Good Brain is saying, they're also looking into doing the acceleration on the video card. However, this is cosmetic effects only, because the main CPU can't see the result. It'll be useful for blowing holes in the fog or throwing up sparks from scrapes and bangs, but it won't change the actual gameplay like a true physics accelerator would.

This is likely to be a very interesting technology. Eventually. This year, I'd give it a pass.
posted by Malor at 8:58 AM on October 9, 2006

This isn't my area of expertise, but in the recent demo of Alan Wake and the intel core 2 quad processor, they were talking about how they just dedicated one of the processing units to handling the physics. If that's the direction things are going (and I have no idea if it is) then the modular physics cards might get obviated before they even catch on.
posted by Hildago at 8:59 AM on October 9, 2006

Yeah, a "physics processor" can't do anything that can't be done just as quickly on a regular CPU -- if you have a regular CPU to spare. I expect multi-core processors will be the way forward.
posted by kindall at 10:42 AM on October 9, 2006

ok, cool. thanks for the info.
posted by crunchland at 1:12 PM on October 9, 2006

Cool, something on AskMeFi that I actually have a clue about :p
I get to review PC hardware for my job; the PhysX card's big problem is that games need to be written specifically to support it; it's not like a CPU or more RAM, it won't speed anything up without a developer making their game compatible. And very few are bothering - unless you're a really big fan of Ghost Recon, there's very little out there which will actually give a PhysX card anything to do.

If you want to play games on a PC, as one of the earlier commenters mentions, you're much, much, much better off spending the $250 on a graphics card.
posted by Sifter at 2:04 PM on October 9, 2006

Well, I only ask because City of Heroes/City of Villains is one of the games that supports it, but when I realized the price, I wanted to know if it was worth it. I suspected it wasn't, but I had an AskMe post burning a hole in my pocket, and thought I'd ask.
posted by crunchland at 5:12 PM on October 9, 2006

Anandtech had a test of the PhysX with that very game, as I recall. The verdict was lukewarm.
posted by stavrosthewonderchicken at 1:02 AM on October 11, 2006