Compare any two graphics cards:
GeForce GTX 470 vs Radeon HD 3870 X2 1GB
IntroThe GeForce GTX 470 comes with a GPU clock speed of 607 MHz, and the 1280 MB of GDDR5 RAM is set to run at 837 MHz through a 320-bit bus. It also features 448 Stream Processors, 56 TAUs, and 40 Raster Operation Units.
Compare all of that to the Radeon HD 3870 X2 1GB, which comes with a core clock speed of 825 MHz and a GDDR4 memory frequency of 1126 MHz. It also features a 256-bit bus, and makes use of a 55 nm design. It is comprised of 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
The Radeon HD 3870 X2 1GB should in theory perform just a bit faster than the GeForce GTX 470 in general. (explain)
Texel RateThe GeForce GTX 470 should be much (more or less 29%) more effective at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)
Pixel RateThe Radeon HD 3870 X2 1GB should be a small bit (about 9%) better at AA than the GeForce GTX 470, and also should be able to handle higher screen resolutions without slowing down too much. (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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 MB per second) that can be transported past the external memory interface within a second. The number is worked out by multiplying the bus width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high 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 amount of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant 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.