NVIDIA’s midrange follow-up to the GeForce 6800 was released in September, under the guise of the GeForce 6600, with the 6600 GT filling the top spot of that line of products. With the NV43 chip that powers the 6600’s being built as native PCI Express this left AGP users, who are in the vast majority at the present time, nowhere to turn if they were attracted to these boards. However, NVIDIA had previously released the "HSI" bridge chip, such that they could convert their AGP based graphics chips to operate on the PCI Express interface – theoretically this HSI bridge could just be reversed in order to enable a PCI Express graphics chip to operate in and AGP interface.

A little over a month later NVIDIA are now ready to unveil the AGP version of 6600 GT. The necessary inclusion of the HSI bridge has resulted in an interesting board design, however while the performance specifications of the PCI Express and AGP versions are close, the full speeds don’t quite make it across to the AGP version. Here we’ll take a closer look at the GeForce 6600 GT for AGP.

The Graphics Chip

Before we take a detailed look at the NVIDIA reference board itself, we'll take a refresher of some of the key properties and specifications of the NV43 chip that is at the core of the 6600 GT:

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The NV43 chip itself does not differ on the AGP board to the PCI Express versions since it is up to the job of the HSI bridge chip to facilitate the translation of the different interface types.

The NV43 chip is fully derived from the NV4x architecture and as such it inherits the same features, albeit at an expected lower performance, as the high end GeForce 6800 Series. Listed below are a few of the key 3D features that are present in the NV4x series:

  • CineFX 3.0 Architecture
    • Full DirectX9 Support
    • DirectX9 Shader Model 3.0 Support
      • Vertex Shader 3.0
      • Pixel Shader 3.0
      • Internal 128-bit Floating Point (FP32) Precisions
    • Unlimited Shader Lengths
    • Up to 16 textures per pass
    • Support for FP16 Texture Formats with Filtering, FP32 without
  • NVIDIA High Precision Dynamic Range Technology
    • Full FP16 Floating Point Support throughout the entire pipeline
    • FP16 Floating Point Frame Buffer Support
  • Intellisample 3.0
    • Up to 4X Native Multi-sampling FSAA with rotated grid sampling
    • Lossless color, texture, z-data compression
    • Fast Z Clear
    • Up to 16x Anisotropic Filtering
  • UltraShadow Technology
  • Advanced Display options
    • Dedicated on-chip video processor
    • nView Multi Display technology
    • Digital Vibrance Control 3.0

For a more detailed look at the feature-set and architecture of the NV4x architecture take a look at our NV40 - GeForce 6800 Ultra preview.