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 clocked the core speed at 600 MHz. The GDDR3 memory works at a speed of 900 MHz on this particular card. It features 112 SPUs as well as 56 TAUs and 16 ROPs.
Compare those specifications to the GeForce 9800 GT 1GB, which comes with a GPU core clock speed of 600 MHz, and 1024 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also is made up of 112 SPUs, 56 TAUs, and 16 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have exactly the same memory bandwidth, so theoretically they should perform the same. (explain)
Texel RateBoth cards have exactly the same texel rate, so theoretically they should perform equally good at at AF. (explain)
Pixel RateBoth cards have exactly the same pixel rate, so theoretically they should perform equally good at at anti-aliasing, and be able to handle 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: Bandwidth is the max amount of information (in units of MB per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's bus width by the speed of its memory. If the card has DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total texture units of the card by the core clock 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 processed in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.