Compare any two graphics cards:
GeForce 8800 GT 512MB vs GeForce 9800 GT 1GB
IntroThe GeForce 8800 GT 512MB makes use of a 65 nm design. nVidia has set the core speed at 600 MHz. The GDDR3 RAM runs at a frequency of 900 MHz on this specific model. It features 112 SPUs as well as 56 Texture Address Units and 16 ROPs.
Compare that to the GeForce 9800 GT 1GB, which has a core clock speed of 600 MHz and a GDDR3 memory frequency of 900 MHz. It also uses a 256-bit bus, and makes use of a 65/55 nm design. It features 112 SPUs, 56 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have the exact same memory bandwidth, so theoretically they should perform exactly the same. (explain)
Texel RateBoth cards have the exact same texel rate, so in theory they should perform equally good at at anisotropic filtering. (explain)
Pixel RateBoth cards have the exact same pixel fill rate, so in theory they should be equally good at at AA, and be able to handle the same resolutions. (explain)
Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.
Please note that the price comparisons are based on search keywords - sometimes it might show cards with very similar names that are not exactly the same as the one chosen in the comparison. We do try to filter out the wrong results as best we can, though.
Memory Bandwidth: Memory bandwidth is the largest amount of information (measured in megabytes per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.