vacancies advertise contact news tip The Vault
facebook rss twitter

Review: NVIDIA's GeForce 6800 and 6800 GT GPUs

by Ryszard Sommefeldt on 13 July 2004, 00:00

Tags: NVIDIA (NASDAQ:NVDA)

Quick Link: HEXUS.net/qaze

Add to My Vault: x

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.