Compare any two graphics cards:
GeForce 8800 GT 1GB vs GeForce 9800 GT 512MB
IntroThe GeForce 8800 GT 1GB features clock speeds of 600 MHz on the GPU, and 900 MHz on the 1024 MB of GDDR3 RAM. It features 112 SPUs as well as 56 TAUs and 16 Rasterization Operator Units.
Compare that to the GeForce 9800 GT 512MB, which comes with GPU clock speed of 600 MHz, and 512 MB of GDDR3 RAM running at 900 MHz through a 256-bit bus. It also features 112 SPUs, 56 TAUs, and 16 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have exactly the same bandwidth, so theoretically they should perform exactly the same. (explain)
Texel RateBoth cards have the exact same texel rate, so theoretically they should be equally good at at AF. (explain)
Pixel RateBoth cards have exactly the same pixel rate, so in theory they should be equally good at at full screen anti-aliasing, and be capable of handling the same screen 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 max amount of information (counted in MB per second) that can be transported across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, 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 amount of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.