NV30 is GeForce FX

Today NVIDIA is announcing NV30.  This greatly anticipated DirectX9 Graphics Processing Unit (GPU), the first to include technology acquired from 3DFX, is finally being released.  It goes by the name of GeForce FX. Bjorn3D was lucky enough to receive a press package from NVIDIA covering, in detail, the features of this new GPU.  With this preview, we’ll look at the extensive features of this next generation product and a take a quick glance at the card.

The GeForce “FX” name was purposely chosen for two reasons:

Technical Highlights

First, let’s look at the new features of this new GPU before we look at the details of the actual video cards that are soon to come.

GeForce FX was designed from the ground up to encompass and surpass Microsoft’s DirectX9 specification.  The core change of DX9 from DX8 is increased programmability.  The programming language was improved with more commands being made available, the structure was made much more flexible for the DX programmers, making it easier to implement.  The areas of concern are the pixel shaders and vertex shaders. 

NVIDIA provided this table, which illustrates the changes in the pixel shader and vertex shader specifications.  The number of instructions has doubled and the constants, used for temporary data storage, has more or less tripled.  Also notice that NVIDIA has taken advantage of the die real estate and included thousands of instructions and constants…calling it Version 2.0+ (more on this in the CineFX discussion below). 

It is generally agreed that the DX8 pixel shaders and vertex shaders were “configurable” and not truly “programmable.”  DX9 brings a whole new level to GPU programmability, and in fact relies upon the programmer’s instructions to be utilized in order to achieve it’s potential. 

The key benefit of the Pixel Shader 2.0 feature set is that it can operate on arbitrary math algorithms that the programmer would have otherwise relied upon the CPU to perform.  The above picture shows how the pixel shaders can be programmed to vary the color of a surface, at the pixel level, based upon the light source location….and this is just the tip of the iceburg.  Procedural shading can also be programmed in a similar manner, which can literally do away with the problems associated with mapping a 2D texture to a 3D surface.  The pixel shaders can actually generate the detailed textures that we’re used to seeing by simply following the rules established by the program.

A similar tale is told by the new Vertex Shaders 2.0 specification.  With the extra instructions and constants available, programmers can generate much more complex scenes due to the larger space available for larger programs in hardware.

Also of importance in Vertex Shaders 2.0 is the inclusion of flow control.  Flow control permits the calculations to branch off into other subroutines in the instruction set.  This is necessary to best automate the construct of the near cinematic effects, which are claimed to be possible.

On the next page, we'll look at NVIDIA's solution to DirectX9.....CineFX