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Nvidia’s First DirectX 10 Chip to Be “Hybrid” Design
Nvidia’s G80 to Have Dedicated Pipelines – Rumours
Despite of the fact that Microsoft’s next-generation graphics application programming interface (API) will be able to take advantage of unified shader processors, at least Nvidia Corp.’s first DirectX 10-capable chip will utilize dedicated pixel and vertex processors, according to some rumours.
Nvidia’s code-named G80 graphics processing unit (GPU) will incorporate 48 pixel shader processors and an unknown number of vertex shader processors, some unofficial sources said. The chip is still expected to support feature-set of DirectX 10 along with Shader Model 4.0, even though it will not take advantage of the unified processors that can compute both pixel and vertex shaders.
Microsoft Corp. pushes unified shader language for pixel and vertex shaders in its Xbox 360 game console ad well as graphics API of Windows Longhorn – Windows Graphics Foundation 2.0, which is sometimes referred as the DirectX 10. As a result of that graphics hardware designers should deliver their chips with unified shader engines at some point in future in order to more efficiently support the new API. However, previously Nvidia Corp. expressed opinions that it would make sense to release architecture with unified shader processors “when it makes sense”.
“We will do a unified architecture in hardware when it makes sense. When it’s possible to make the hardware work faster unified, then of course we will. It will be easier to build in the future, but for the meantime, there’s plenty of mileage left in this architecture,” David Kirk, who is Nvidia’s chief architect, said in an interview with Bit-tech.net web-site.
ATI Technologies has already developed a unified shader architecture used in the Xenos graphics processor of the Xbox 360 game console. Nvidia believes that it is much harder to design a processor with unified pixel and vertex shader processors, as it is not a trivial task to create appropriate load balancing logic that would arbiter the unified arithmetic logic units.
The new DirectX 10 API is expected to be released later this year along with Microsoft Windows Vista operating system.
Nvidia did not respond to enquiry seeking for comment. Typically, the company does not comment on unreleased products."
http://www.xbitlabs.com/news/video/display/20060220100915.html
Tal como eu suspeitava, e o David Kirk dizia aqui:
Microsoft have written a unified software layer into the next version of WGF. Does this signify that Microsoft and ATI are on the same track, and NVIDIA are not following the same path?
"Well, let's get something straight. Microsoft makes APIs (Application Programming Interfaces- Ed) not hardware. WGF is a specification for an API specification - it's software, not hardware."
"For them, implementing Unified Shaders means a unified programming model. Since they don't build hardware, they're not saying anything about hardware.
"Debating unified against separate shader architecture is not really the important question. The strategy is simply to make the vertex and pixel pipelines go fast. The tactic is how you build an architecture to execute that strategy. We're just trying to work out what is the most efficient way.
"It's far harder to design a unified processor - it has to do, by design, twice as much. Another word for 'unified' is 'shared', and another word for 'shared' is 'competing'. It's a challenge to create a chip that does load balancing and performance prediction. It's extremely important, especially in a console architecture, for the performance to be predicable. With all that balancing, it's difficult to make the performance predictable. I've even heard that some developers dislike the unified pipe, and will be handling vertex pipeline calculations on the Xbox 360's triple-core CPU."
"Right now, I think the 7800 is doing pretty well for a discrete architecture?
So what about the future?
"We will do a unified architecture in hardware when it makes sense. When it's possible to make the hardware work faster unified, then of course we will. It will be easier to build in the future, but for the meantime, there's plenty of mileage left in this architecture."
http://www.bit-tech.net/bits/2005/07/11/nvidia_rsx_interview/4.html
