NVIDIA GeForce3 Technology Preview

Many of the GeForce3's enhancements hinge greatly on DirectX 8 support. In fact, the supported features of DirectX 8 look eerily similar to the feature list of the GeForce3. The major change for DirectX 8 seems to be the emphasis on the programmability of Vertex and Pixel Shaders, as opposed to the static or fixed function models used in previous versions.

There is no doubt that NVIDIA played a very important role in the design of DirectX 8 and stands to gain the most from its acceptance. This symbiosis is the result of a highly cooperative relationship between NVIDIA and Microsoft, with Microsoft actually licensing NVIDIA programmable Pixel and Vertex Shaders technology for DirectX 8. Having the GeForce3 implemented in the upcoming X-Box undoubtedly helped, since Microsoft would surely want a full set of X-Box design tools and APIs specifically related to the GeForce3 GPU.

While it represents a major coup for NVIDIA, it also brings up some troubling questions, such as how competing video cards can become DirectX 8 complaint. Although there are varying degrees of compatibility and compliance, the GeForce3 is currently the only chipset that is fully compliant with the DirectX 8 specification. With NVIDIA licensing portions of the API to Microsoft, the GeForce3 could conceivably remain the sole holder of this designation for quite some time.

Developer Support

If the success of the GeForce3 hinges greatly on DirectX 8, then developer acceptance is a key ingredient in that formula. NVIDIA has been doing their best to get nfiniteFX Engine SDKs and coded effects into the hands of key developers to help them transition over fully to DirectX 8. On the application side, Autodesk has even re-tooled their popular 3D Studio MAX (or 3ds max) graphic and visual effects software to make full use of GeForce3 functionality. Since 3D Studio MAX is a heavy player in 3D content development, they have seen the writing on the wall and probably anticipate a high rate of DirectX 8 developer adoption.

On the 3D PC game side, developer support looks solid. Aquanox looks to be the major launch title for the GeForce3, and it relies heavily on the programmable vertex and pixel shaders to bring it underwater environment to life. Other games supporting the technology, such as Ballistics, Crazy Car Championship, Dronez, Everglade Rush, and Incoming Forces, seem to revolve around the "racing/apocalyptic battle" genre that has become so prevalent whenever a new 3D technology has emerged. The screenshots certainly looked good and bode well for the future of the nfiniteFX technology.

Along that line, the Unreal Engine looks to be getting a DirectX 8 overhaul through the use of vertex and pixel shaders. Improvements such as faster character animations, higher polygon counts, better lighting effects and palette skinning have been added due to the nfiniteFX technology and DirectX 8.

Since the GeForce3 and its nfiniteFX Engine will be present in the X-Box, this also gives NVIDIA's development acceptance program a huge shot in the arm. While the sheer number of potential X-Box developers is large enough to assure GeForce3 mass acceptance, there are also some other inherent benefits. Cross platform portability will be much easier between the X-Box and PC, and the inherent advantages in market share and revenue streams virtually assure that many games and applications will appear in both X-Box and PC formats. By only needing to learn one basic set of tools, X-Box teams could also transition to PC development, or vice versa, with much less time for skills retooling. The GeForce3 may be the closest we ever come to having a portable standard between PCs and game carts.

The GeForce3 GPU

So far we have covered the new technologies, features and enhanced memory performance of the GeForce3, so it is time to take a closer look at the chip itself. The GeForce3 is produced on a .15 micron process, compared to the .18 micron design of the GeForce2, and includes an amazing 57 million transistors. Taken as a total package, including the new features such as programmable Vertex and Pixel Shaders, Lightspeed Memory Architecture, High-Resolution Antialiasing, and integrated DirectX 8 support, and the GeForce3 is a major enhancement over the current NVIDIA offerings.

The basic hardware specifications of the GeForce3 GPU tell a bit different story. Other than the enhancements listed above, the basic architecture of the GeForce3 remains very similar to that of the GeForce2. Both GPUs include quad pixel pipelines, which at the proposed 200 MHz core/460 MHz memory design of the GeForce3, translates into a fill rate of 800 Megapixels/sec. This is right on line with the fillrate of the GeForce2 GTS and Pro versions, and below the 1 Gigapixel/sec fillrate of the GeForce2 Ultra. GeForce3 memory bandwidth will be 7.36GB/sec, or equal to that of the GeForce2 Ultra. The stock GeForce3 will also ship with a full complement of 64 MB of DDR RAM.

This is just one side of the performance coin and the GeForce3 documentation states that each pixel shader can now handle 4 texels per pass, as compared to the 2 texels per pass of the GeForce2 models. This translates into the GeForce3 having the promoted 3.2 billion AA samples/sec fill rate. How greatly this additional texel processing affects overall performance will depend on the multi-texture and DirectX 8 support of the application.

When running DirectX 8 applications coded specifically for its enhanced features, the GeForce3 should be in a class by itself. Even if the raw performance specs are roughly equivalent to the high end GeForce2 cards, the GeForce3's enhanced hardware, features and memory bandwidth will likely win the day. The addition of memory bandwidth enhancements helps alleviate one of the pressing concerns of GeForce2. Even with these advantages, there is still potential for the GeForce3 to be outperformed by the older GeForce2 Ultra when using legacy 3D programs. Still, the GeForce3 does offer some inherent benefits to legacy programs, such as enhancing image quality through HRAA, while maintaining playable framerates.

First on Mac

In a surprising move, NVIDIA will offer the GeForce3 first as an option on the Mac. In fact, the Apple website has featured GeForce3 advertisements and offers for some time, and the card is scheduled for Mac deployment in under a month. While the move seem illogical on the surface, NVIDIA has been taking steps to get the Mac user onboard and their website has many statements relating to the GeForce2 being "designed with the Apple Macintosh platform in mind".

It seems that NVIDIA has turned their attention to the Mac arena, which just happens to be the stomping ground of their old friend ATI. Do not underestimate the relative performance leap that the GeForce3 represents to the Mac user, especially considering that the GeForce2 MX is currently the fastest NVIDIA Mac solution. The strategy seems to be to wow the Mac crowd with incredible framerates, make inroads into historically ATI territory, and give PC developers even more time to release their DirectX 8 software.

Conclusion

With the release of the GeForce3, NVIDIA seems to be ringing the developer dinner bell quite loudly. The ability to use the nfiniteFX Engine to program vertex and pixel shaders gives developers the tools to create custom effects and help differentiate their products from the rest of pack. Best of all, the GeForce3 is tied directly to the DirectX 8 API, something that developers will be making use of anyway. This should translate into a high adoption rate of the new DirectX 8 specification, and in turn reap high rewards for the DX8-compliant GeForce3.

For early adopters of the GeForce3 consumer technology there is the prospect of playing DirectX 8 enhanced games in the near future, as well as the addition of hardware HRAA, increased memory bandwidth efficiency and sufficient horsepower to play the current crop of games. The GeForce3 is a different sort of product from NVIDIA, who has taken a bold step in favor of more stunning visuals and memory enhancements, rather than simply raising the clock speed to gain a few more fps in Quake III.

Vince Freeman

Skip To Page 1 Introduction / The nfiniteFX Engine / Vertex Shaders 2 Programmable Pixel Shaders 3 NVIDIA GeForce3 Specifications and Features 4 Lightspeed Memory Architecture / Higher Order Surfaces / Crossbar Memory Controller 5 Lossless Z Compression / Z-Occlusion Culling / High-Resolution Antialiasing (HRAA) • 6 DirectX 8 / Developer Support / The GeForce3 GPU / First on Mac / Conclusion

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