By volt - May 12, 2003

NV35 Technology

Since the introduction of R300 VPU from ATI, NVIDIA has been struggling to reclaim the performance and image quality crowns (Some like NVIDIA's quality output and some don't. That being said, in my opinion R3x0 has a better overall IQ than NV30). You may recall a conference at Cannes where Jen-Hsun Huang, the CEO of NVIDIA confessed that GeForce FX 5800 Ultra hasn't delivered the performance everyone anticipated. But is NV30 really a flop? Not at all. Early jump to .13 process and DDR II RAM implementation contributed to the delay and scarce availability. NV30 was just a start...yes a bad start, but I don't suppose you can rule all the way down the line and hold the crown forever?

Can NVIDIA reclaim both crowns? Well let's take a look.

NV35 Lineup:

• GeForce FX 5900 Ultra: Highest performance production GPU, sporting 256MB of RAM. $499 ESP *available June
• GeForce FX 5900: Blazing fast 128MB solution. $399 ESP
• GeForce FX 5800: Also 128MB based solution. $299 ESP

So what's the big deal with the new enthusiast GPU's from NVIDIA?

• FlowFX has been dropped. The new cooling system looks similar to GeForce FX 5800, surrounded by RAM heatsinks. What we have here is a bracket that occupies two slots, though there is a big probability the retail cards will sport a single slot bracket.

• 256-bit Memory Architecture
• Two performance modes: 2D and 3D (For more information read our GeForce FX 5900 Ultra Preview)
• Raw bandwidth: 27.2 GB/sec
• Up to 256MB of DDR I / DDR II RAM
• CineFX 2 For Cinematic Special Effects
• Ultra Shadow Architecture (Shadow Volume Acceleration for next generation games such as Doom III)
• IntelliSample HCT; enhanced antialiasing
• New Antialiasing and Anisotropic filtering Techniques
• 2nd Generation Compression and Caching (4 to 1)
• True 128-bit floating-point color per pixel
• Full DirectX 9 and OpenGL support
• Advanced shader operations in OpenGL through extensions

*With the introduction of NV30, NVIDIA claimed that it can do 8 pixels per clock. Earliest revelations over at Beyond3D proved it wrong. NV30 could do 8 pixels per clock only in the following situations (Supposedly only Color+Z is ran at 4 pixels per clock):

• shader operations
• texture operations
• stencil operations
• z-rendering

NVIDIA states that NV35 can do Up to 8 pixels per clock cycle, which highly indicates that the architecture hasn't changed (4 pipelines with two texture units per pixel pipeline). I just haven't had enough information to confirm that.

256-bit Memory Controller

Finally a memory controller that deserves few words. By moving to 256-bit memory controller, NVIDIA has almost doubled the raw bandwidth on NV35 GPU (27.2 GB/sec). The new controller will allow for increased efficiency and overall throughput, especially at higher resolutions such as 1280x1024 and 1600x1280. Fill rate is everything™ some say :)

CineFX 2.0

• The improved CineFX implementation will provide for a 2X increase in floating point pixel shader performance (Note that NV30's pixel shader performance was poor compared to R300's).
• NVIDIA's GeForce FX 5900 and FX 5900 Ultra GPUs will sport UltraShadow technology (Shadow Volume Acceleration):

Figure 1. Programmers can define a subset of the scene (within z-min and z-max) to limit lighting/shadow calculations to the appropriate area for each light source.

Speeding Up Shadows

Accurate shadows are key for realistic and believable scenes. The complex interactions between multiple light sources and numerous objects and characters involve multiple-pass programming. For every frame, every light source must be analyzed relative to every object. The patent-pending UltraShadow technology can be applied to today’s games to introduce stunning visual effects that create distinctive looks and digital environments, that can set a game apart from the competition.

Software Advances

UltraShadow gives programmers the ability to calculate shadows much more quickly by eliminating unnecessary areas from consideration. With UltraShadow, programmers can define a bounded portion of the scene (often called depth bounds) that limits calculations of lighting source effects to objects within a specified area. (See Figure 1.) By limiting calculations to the area most affected by a light source, the overall shadow generation process can be greatly accelerated. Programmers can fine-tune shadows within critical regions, create incredible
visualizations that effectively mimic reality, and still achieve awesome performance for fast-action games. The accelerated shadow generation can also free up time that can be allocated to other sophisticated but time-consuming effects.

Hardware Advances

Because stenciled shadow volumes require no texturing or color updates, the hardware “doubles up” the rendering horsepower to generate stenciled shadow volumes at speeds of up to double the standard pixel-processing rate. Other graphics solutions have to render stenciled shadow volumes in two passes. UltraShadow accomplishes the shadow volume rendering in a single pass, reducing CPU overhead and improving GPU performance. The NVIDIA approach also interoperates with NVIDIA Intellisample™ high-resolution compression technology (HCT) to make sure that shadow edges are properly antialiased. The GeForce FX 5900 GPUs maintain the stencil information on a sub-pixel basis, ensuring that shadow edges are antialiased rather than “blocky” or “jaggy.”

Applications

Anytime a game or application calculates shadows, UltraShadow will enhance the application performance. The more passes that are required for the lighting and shadow calculations—for example, scenes that involve multiple light sources and many physical objects in sight—the more significant the performance improvement, with the most complex scenes achieving the most noticeable results. Emerging next-generation games, such as Doom III and Abducted, will see dramatic improvements in execution speeds. The GeForce FX 5900 GPUs with UltraShadow technology continue to enable a new generation of gaming effects.

In simple terms, how will we benefit from this technology? More realistic shadows from multiple sources. A specific area of an object in a scene can be shadowed for more realistic effects. Concluding, UltraShadow™ appears to be a very promising technology, it's just a matter of time until we see it in action (Doom III).

IntelliSample HCT

The FX 5900 GPU will be able to deliver enhanced Z and Color compression as well as accelerated texture compression capabilities. Although it's still 4 to 1 technology, the new compression will improve antialiasing performance and image quality. IntelliSample HCT will allow for up to 50 percent increase in compression efficiency.

The rest of the features are NV30 related which were discussed by Mike in his GeForce FX preview.

Conclusion

Can NVIDIA deliver this time? There is only one way you can find out. Read Mike's GeForce FX 5900 Ultra preview. Based on the information given to me, FX 5900 Ultra (256MB RAM) and FX 5900 (128MB RAM) should do a fine job competing against Radeon 9800 Pro at all modes. Whether the chip design was greatly improved we could rattle about this all day long. Let's just hope we don't see any hacks in the drivers this time, because that's a bad sign.

NVIDIA will announce their new NV35 GPU today during the press conference at their HeadQuarters. Make sure you go (If you can). Will they show off Four Dawns running around? I bet that's what you wished for! Oh and don't forget about Detonator FX! It's coming.

-A fellow NVIDIOT