- 525MHz Core clock speed
- 278 million transistors
- 90 nanometer low-k process
- 20 Pixel Shader Pipelines
- 16 ROPs
- 5 Vertex Shader Pipelines
- DirectX 9.0c
- Pixel Shader 3.0
- Vertex Shader 3.0
- HDR
- Up to 4x MSAA (8XS with mixed SS+MS)
- Up to 16x AF
- OpenGL 2.0
The 7900GS chip is based upon NVIDIA's G71 chip that is a development of the G70 chip introduced with the GeForce 7800GTX in April 2005. The 7900 series was the first NVIDIA video chip produced on TSMC's 90 nanometer process and the chip contains 278 million transistors. NVIDIA has traditionally doubled the number of transistors in their video chips every year or two (GeForce 1999 (15 million), GeForce 2 GTS 2000 (25 million), GeForce 3 (57 million), GeForce4 2002 (60 million), GeForce 5 2003 (120 million), GeForce 6 2004 (178 million), GeForce 7 2005 (321 million), GeForce 8 2006 (621 million) and the 7900 series was the first to break that tradition.
GeForce 7900GS is fully Shader Model 3.0 compliant. The key advantages of Pixel Shader 3.0 over 2.0 include longer shader program lengths, vertex texturing and the ability to do dynamic branching. The key advantages of Vertex Shader 3.0 over 2.0 include longer shader lengths and the ability to do HDR rendering. The 7900GS is called Microsoft Vista Ready by NVIDIA, in that it is able to use the new Windows Aero Glass GUI. The 8800GTX and GTS are the only cards available today to fully support Vista's new API, DirectX 10. It is likely that NVIDIA will not launch a replacement for the 7900GS until sometime in the New Year.
Anti-aliasing is important to me as an image quality freak. After all, what's the sense of playing games if they are a big jaggy mess? The 7900GS is capable of up to 2x MSAA in a single cycle with 4x MSAA available for two cycles. 6XS is a mix of 2X MSAA+2x SSAA. 8XS is 4x MSAA+2x SSAA but is also the most costly in terms of performance in games. Another facet of image quality is the sharpening of textures far away from the viewer or anisotropic filtering. The 7900GS AF is a lot worse than ATI's by default due to the angle independency of the X1K series, but the 8800 series has retaken the AF IQ lead to NVIDIA.
One recent trend has to use Floating Point Blending in games to do High Dynamic Range lighting. The normal computer video card cannot do floating point calculations for lighting leaving a maximum range of 255:1 for the contrasts in a scene. This is why games before the advent of the RADEON 9700 Pro and GeForce 6800 looked dull. Today every video card is capable of floating point calculations 16-bit, and the 8800 is capable of 32-bit FP lighting calculations. Oblivion uses HDR in virtually every scene, naturally lighting the leaves in the tree, the armor, the sky and more.
