NVIDIA GeForce 6600 GT - AGP Version


Back in September, NVIDIA released the latest of their line of mid-range or value priced video cards, dubbed the GeForce 6600.  The only version available at the time, however, was for PCI-Express, which left many users out in the cold since the standard had only been available on brand new motherboards based on the i915/i925 chipsets.  Now, nearly two months later, we finally have an AGP version of the 6600 GT to run through some benchmarks and see how it stacks up with some other comparable mid-range cards.

NVIDIA's take on the 6600 GT AGP is that it should be looked at as a "9800 Pro" killer.  Essentially, they are pitting this new card with all of the features of their high-end 6800 line, against ATI's former flagship video card.  This match up has more to do with price-point competition, rather than comparing the cards' feature sets.  On paper, there's really no way for the 9800 Pro to keep with up with the more advanced 6600 GT, but in retail markets, the two cards find themselves in the same price bracket (the "magical" sub-$200 mainstream video card).

Today's goal is to see how these two cards stack up against each other.  And we've thrown in last year's mainstream darling, the GeForce FX 5900XT, for some quick comparisons as well.  Jeff has already covered the basics of the 6600 architecture in his preview and final review of the PCI-E version, so instead of rehashing old information, we'll offer some quick specs on the GeForce 6600 GT instead, and then move directly to benchmarking.

Specifications & Features of the GeForce 6600 GT
NVIDIA's Newest Value GPU, only now for AGP!


  • Vertex Shaders
    Support for Microsoft DirectX 9.0 Vertex Shader 3.0
    Displacement mapping
    Geometry Instancing
    Infinite length vertex programs*
  • Pixel Shaders
    Support for DirectX 9.0 Pixel Shader 3.0
    Full pixel branching support
    Support for Multiple Render Targets (MRTs)
    Infinite length pixel programs*
  • Next-Generation Texture Engine
    Up to 16 textures per rendering pass
    Support for 16-bit floating point format and 32-bit floating point format
    Support for non-power of two textures
    Support for sRGB texture format for gamma textures
    DirectX and S3TC texture compression
  • Full 128-bit studio-quality floating point precision through the entire rendering pipeline with native hardware support for 32bpp, 64bpp, and 128bpp rendering modes


  • Full floating point support throughout entire pipeline
  • Floating point filtering improves the quality of images in motion
  • Floating point texturing drives new levels of clarity and image detail
  • Floating point frame buffer blending gives detail to special effects like motion blur and explosions


  • Advanced 16x anisotropic filtering
  • Blistering-fast anti-aliasing and compression performance
  • New rotated-grid anti-aliasing removes jagged edges for incredible edge quality
  • Support for advanced lossless compression algorithms for color, texture, and z-data at even higher resolutions and frame rates
  • Fast z-clear
  • High-resolution compression technology (HCT) increases performance at higher resolutions through advances in compression technology


  • Designed to enhance the performance of shadow-intensive games, like id Software's Doom III


  • Designed for AGP 3.0
  • Supports for AGP 8X including Fast Writes and sideband addressing
  • Utilizes high-speed GDDR3 memory from Samsung
  • 128-bit advanced memory interface
  • 0.11 micron process technology
  • Advanced thermal management and thermal monitoring
  • Dedicated on-chip video processor
  • MPEG video encode and decode
  • WMV9 decode acceleration
  • Advanced adaptive de-interlacing
  • High-quality video scaling and filtering
  • DVD and HDTV-ready MPEG-2 decoding up to 1920x1080i resolutions
  • Dual integrated 400 MHz RAMDACs for display resolutions up to and including 2048x1536 at 85Hz.
  • Dual DVO ports for interfacing to external TMDS transmitters and external TV encoders
  • Microsoft Video Mixing Renderer (VMR) supports multiple video windows with full video quality and features in each window
  • Full NVIDIA nView multi-display technology capability


  • DVC color controls
  • DVC image sharpening controls



  • Complete DirectX support, including the latest version of Microsoft DirectX 9.0
  • Full OpenGL, including OpenGL 1.5

* The operating system or APIs can impose limits, but the hardware does not limit shader program length.

NVIDIA GeForce 6600 GT
GPU Core Clock: 500 MHz
Memory Clock: 450 MHz (900 MHz effective)
Fillrate: 4000 Mpixels/s
Memory Bandwidth: 16.0 GB/s


Even though the specifications remain mostly the same, we've noticed quite a few differences in architecture between this model and the PCI-Express version before it.  The GeForce 6600 GT AGP is still an 8 Pixel Pipeline card driven by a 500MHz GPU backed by 128MB of Samsung GDDR3 RAM, but now running at 450MHz (900MHz effective).  Without the power output of the PCI-Express bus, the AGP version of the 6600 GT requires an external power source, so be prepared to have that power cable splitter handy.  Gone are the SLI pins along the top of the card, since dual AGP slots are not possible.  Also, this model sports two DVI-I connectors and an S-Video port - there isn't any standard 15-pin DB15 VGA port on the card.  Obviously, for the still large CRT monitor fan base, a DVI-to-VGA adapter will probably be included in any retail package. 




The last major difference that we came across had to do with the placement of the GPU and RAM.  Whereas we had seen a typical square configuration with the other card, the new 6600 GT we received had the GPU placed on an angle with the RAM rotated to match.  Thus, the main heatsink/fan combo is also placed on an angle to cover the GPU.  It doesn't, however, make direct contact with any of the RAM chips, so these chips don't benefit from any extra cooling.  The HSF on the card we received came adorned with a Hellknight from Doom 3, a not-too-subtle hint as to what this card is geared for.  A smaller, passive heatsink has been added to the south of the main one which covers the HSI (High Speed Interconnect) chip, which handles the bridge between PCI-Express and AGP.  The 6600 GT is a native PCI Express GPU, so the HSI chip is used to translate AGP calls to PCI Express.


Tags:  Nvidia, GeForce, force, GT, AG, id

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