NVIDIA's Next-Generation Architecture July 25, 2002 Brandon Bell

Introduction

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Accelerating the convergence of film and real-time rendering

Although summer is still young, things are definitely beginning to heat up in the 3D graphics market. Matrox kicked things off with its re-entrance into the high-end graphics market with its Parhelia graphics card. Then, just last week ATI unveiled its RADEON 9000 DirectX 8 board and its next generation RADEON 9700 graphics card. Not wanting to be left out of the party, NVIDIA has chosen to use SIGGRAPH to unveil new details on its next generation graphics core, which is taking place this week in San Antonio. Unlike an event like Comdex, SIGGRAPH is geared solely towards the professional graphics community. This makes it a natural fit for NVIDIA to unveil new details on its graphics hardware: the content developers and engineers that use NVIDIA’s hardware on a daily basis are all right there.

Moving beyond nfiniteFX

The key message NVIDIA plans to deliver with the NV3x family is the cinema quality graphics effects it brings to the table. This is something we’ve been hearing from NVIDIA for quite awhile now, and ultimately reached reality when NVIDIA demonstrated a Quadro GPU rendering scenes from Final Fantasy: The Spirits Within at SIGGRAPH 2001 last summer. As impressive as that demonstration was, NVIDIA feels it has taken an even greater step forward in bringing the world of film to the PC with its next generation graphics technology. To highlight this, NVIDIA has chosen the moniker “CineFX” to brand the graphics engine of its next generation graphics processor. While NVIDIA hasn’t disclosed the complete details of its new CineFX architecture, a few morsels of information have just been revealed.

[image]

possible on the NV30

-John Carmack, Lead Programmer, id Software

Pixel shaders

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Pixel processing

Remember how John Carmack was disappointed with the pixel processing implementation in DirectX 8 and the GeForce3 GPU? With CineFX, NVIDIA has elevated pixel processing to the same level of importance as vertex processing.

For instance, many of the instructions used solely for vertex processing are now available for pixel processing, and the programs themselves can be longer (up to 1024 instructions). And while GeForce3 was limited to up to four textures per pixel, NV3x supports up to 16. Finally, the number of pixel operations is drastically increased. While DirectX 8 was limited to eight, and Microsoft’s upcoming DirectX 9 supports up to 64 pixel operations, NV3x supports up to 1,024 texture operations. This includes such advanced instructions as swizzling, and conditional write masks.

As a result of these improvements, developers will be able to have more control at the pixel level, resulting in even more realistic graphics effects.

Higher color precision

Another new improvement introduced with NV3x is support for 64-bit and 128-bit color (16 or 32-bit floating point for each RGB component). As you can imagine, this results in images with more vibrant color ranges. A common example is fog. Chances are, if you’ve played lots of games with extensive use of fog or smoke, artifacts were frequently visible. With a wider color range these artifacts are eliminated.

Obviously 128-bit color comes at a greater performance penalty, which is why developers can pick and choose which color mode they wish to use for each application. For extremely high-resolution textures, the 32-bit floating-point format (128-bit color) can be used, while others rely on the 16-bit format for added performance.

NV2x and NV3x Comparison
	NV2x	NV3x
Higher Order Surfaces
High Order Surfaces	X	X
Continuous Tesselation	X	X
Vertex Displacement Mapping		X
Geometry Displacement Mapping		X
Vertex Shaders	1.1	2.0+
Max Instructions	128	65536
Max Static Instructions	128	1024
Max Constants	96	256
Temporary Registers	12	16
Max Loops	0	64
Static Flow Control		X
Dynamic Flow Control		X
Pixel Shaders	1.1	2.0+
Texture Maps	4	16
Max Texture Instructions	4	1024
Max Color Instructions	8	1024
Max Temp Storage		64
Data Type	INT	FP
Data Precision	32-bit	128-bit

SIDEBAR: Pixar rendered Toy Story 2 in 64-bit color mode.

Final Thoughts

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NVIDIA’s recent announcements give us a glimpse of what NV3x will be capable of, although there are still quite a few details that have not been announced. We haven’t been given clock speeds of the graphics core or memory subsystem, nor do we know any fill rate or other numbers that can be used as a metric of performance. Instead what we are given is a look at just what is possible with NV3x, and based on what we’ve seen so far it should match up very closely with ATI’s RADEON 9700. Other details that we do know is that NV3x will be built off TSMC’s 0.13-micron manufacturing process, will fully support AGP 8X, and supports high-speed DDR-II memory.

In terms of availability, all we know is that NVIDIA has timed NV3x’s release with that of Microsoft’s DirectX 9 API. This puts NV3x somewhere in the fall timeframe, which, if ATI holds up to its RADEON 9700 release schedule, gives ATI a one to three month time-to-market advantage over NVIDIA.

Speaking of the RADEON 9700, a lot of preliminary performance estimates have popped up over the web. All of these comparisons have pitted a prototype RADEON 9700 board against the current performance king, NVIDIA’s GeForce4 Ti 4600. It will be interesting to see what configuration final RADEON 9700 boards will ship in, and just how great a performance advantage RADEON 9700 possess when it is launched. We wouldn’t be surprised to see RADEON 9700 ship in 30 days, retake the performance crown from NVIDIA, and NVIDIA subsequently slash prices on its entire GeForce4 line. Once NV3x is released, NVIDIA could then restore its presence in the $400 high-end market.

This is just one contingency plan NVIDIA may have in the works. We’ve also heard rumors that NVIDIA is hard at work on an NV25 successor with AGP 8X graphics.

Whatever ends up happening, one thing is for sure, we haven’t seen this level of competition since around this same time last year. With Matrox and 3D Labs also playing in the same field (although to a lesser extent) things are even more interesting. This gives consumers choices in the marketplace, and that is definitely a good thing.






SIDEBAR: Will NV3x retake the performance crown, or do you have your money on ATI? Voice your thoughts in the comments!