Compare any two graphics cards:
GeForce 8800 GT 512MB vs GeForce 9800 GT 512MB
IntroThe GeForce 8800 GT 512MB has a core clock frequency of 600 MHz and a GDDR3 memory speed of 900 MHz. It also features a 256-bit bus, and makes use of a 65 nm design. It is made up of 112 SPUs, 56 Texture Address Units, and 16 ROPs.
Compare all that to the GeForce 9800 GT 512MB, which features a clock frequency of 600 MHz and a GDDR3 memory frequency of 900 MHz. It also makes use of a 256-bit bus, and uses a 65/55 nm design. It features 112 SPUs, 56 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have the exact same bandwidth, so in theory they should perform exactly the same. (explain)
Texel RateBoth cards have exactly the same texel fill rate, so in theory they should perform equally good at at anisotropic filtering. (explain)
Pixel RateBoth cards have exactly the same pixel rate, so in theory they should perform equally good at at AA, 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 largest amount of data (in units of megabytes per second) that can be transferred over the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory speed. If the card has DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 applied in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.