NVIDIA GeForce 8800 GTX and 8800 GTS: Unified Powerhouses
The Lumenex Engine
With the GeForce 8800 series architecture, NVIDIA is introducing their new "Lumenex Engine". The Lumenex engine is the name NVIDIA has come up with to describe a host of features integrated in the G80 GPU. The new key features in the Lumenex Engine include 16x Coverage Sampling Anti-Aliasing (CSAA), 16x nearly angle independent anisotropic filtering, 16-bit and 32-bit floating point texture filtering, fully orthogonal 128-bit High Dynamic Range (HDR) rendering with all the above features, and a full 10-bit display pipeline.
CSAA and Angle Independent Anisotropic Filtering:
Coverage Sample Anti-Aliasing is a new anti-aliasing technique that increases image quality, without drastically increasing the demands placed on the GPU or the memory subsystem. In its standard modes, CSAA compresses the redundant color and Z/stencil information into the memory footprint and bandwidth of 4X multi-sample AA. In its higher quality modes (8xQ and 16xQ), CSAA compresses the information in the footprint and bandwidth of 8X multi-sample AA. Previous generations of NVIDIA GPUs could only do 4X MSAA in hardware.
The image above demonstrated the difference between no anti-aliasing, traditional 4X multi-sampling AA and 16x CSAA. In the "NO AA" portion of the image there are sharp, jagged edges. 4X MSAA does a nice job of softening the edge, but the gradient steps are still clearly visible. The 16X CSAA portion of the images has takes things even further though, and are gradient steps are much less apparent.
The GeForce 8800 GPUs also feature a new, high-quality anisotropic filtering engine that eliminates the angle dependant optimizations used in previous GPUs. We talk more about the 8800's new anisotropic filtering and anti-aliasing modes a little later.
10-Bit Display Pipeline:
The Lumenex Engine inside the GeForce 8800 series GPUs is built with a full 10-bit display pipeline. This will allow for over a billion unique colors to be displayed with next-gen 10-bit content and displays, but for now, because multiple stages in the pipeline support 10-bit precision, not just the DACs like some older architectures, data integrity is preserved and the final output should be closer to the original input signal.
The High Dynamic Range (HDR) lighting capabilities inherent in all GeForce 8800 Series GPUs now supports 128-bit precision (32-bit floating point values per component), and unlike previous NVIDIA GPUs, HDR lighting effects can now be used in conjunction with multi-sample anti-aliasing. With the GeForce 8800 series, MSAA is now compatible with both FP16 (64-bit color) and FP32 (128-bit color) render targets.
The updated PureVideo Engine in the GeForce 8800 series of products also allows for more sophisticated post-processing with HD content. In addition to the capabilities already offered by the PureVideo engine in the GeForce 6 and 7 series of products, the GeForce 8800 series adds support for VC-1 and H.264 HD Spatial-Temporal Deinterlacing, VC-1 and H.264 HD Inverse Telecine, HD Noise reduction, and HD Edge enhancement.