NV40 Differences
| 6800 Ultra | 6800 GT | 6800 | |
| Process | 130nm @ IBM | 130nm @ IBM | 130nm @ IBM |
| Transistor Count | 222M | 222M | 222M |
| Geometry Pipeline | VS3.0 | VS3.0 | VS3.0 |
| Fragment Processor | PS3.0 | PS3.0 | PS3.0 |
| Fragment Processor Setup | 2 full ALU (not equal) each with 1 mini ALU, Fog ALU, per pipe | 2 full ALU (not equal) each with 1 mini ALU, Fog ALU, per pipe | 2 full ALU (not equal) each with 1 mini ALU, Fog ALU, per pipe |
| Fragment Processor Precision | FP32, FP16 | FP32, FP16 | FP32, FP16 |
| Traditional Render Setup | 16 x 1 | 16 x 1 | 12 x 1 |
| Vertex Shaders | 6 | 6 | 5 |
| Basic Texture Filtering | Bilinear | Bilinear | Bilinear |
| Texture Filtering | Bilinear, Trilinear, 16X Anisotropic | Bilinear, Trilinear, 16X Anisotropic | Bilinear, Trilinear, 16X Anisotropic |
| Antialiasing | Multi-sampling and super-sampling | Multi-sampling and super-sampling | Multi-sampling and super-sampling |
| AA Sample Type | Rotated grid up to 8X with supersampling combined at 8X | Rotated grid up to 8X with supersampling combined at 8X | Rotated grid up to 8X with supersampling combined at 8X |
| Bus Support | AGP8X | AGP8X | AGP8X |
| Memory support | GDDR3 | GDDR3 | DDR |
| Basic Core Frequency | 400MHz | 350MHz | 335MHz |
| Basic Memory Frequency | 1100MHz | 1000MHz | 700MHz |
| Memory Bus Width | 256-bit, memory crossbar | 256-bit, memory crossbar | 256-bit, memory crossbar |
| Basic Pixel Fillrate | 6400Mpixel/sec | 5600Mpixel/sec | 4020Mpixel/sec |
| Basic Multitexture Fillrate | 6400Mtexel/sec | 5600Mtexel/sec | 4020Mpixel/sec |
| Basic Memory Bandwidth | ~35.2GB/sec | ~32.0GB/sec | ~22.4GB/sec |
The table above highlights the differences between the three 6-series variants. The blue rows are where implementation details differ, be that in clock speeds or other functionality. Fields in red highlight functional changes only in that variant, of which all occur for the plain 6800. The implementation of only three quad pipelines and five vertex shader units, as opposed to the four quad pipe and six VS units on the GT and Ultra, mark out the main differences the plain 6800 has. The clock speed variations do the rest, with the plain 6800 also using cheaper DDR memory, unlike the GDDR3 that the GT and Ultra make use of.
That gives three clearly defined variants at three distinct price points. What about the boards themselves? I've already examined the Ultra board for the inital review, here. Time to look at the GT and plain 6800.
