Compare any two graphics cards:
GeForce 9800 GT 512MB vs Radeon HD 3870 X2 512MB
IntroThe GeForce 9800 GT 512MB makes use of a 65/55 nm design. nVidia has clocked the core speed at 600 MHz. The GDDR3 RAM is set to run at a frequency of 900 MHz on this model. It features 112 SPUs along with 56 Texture Address Units and 16 ROPs.
Compare that to the Radeon HD 3870 X2 512MB, which makes use of a 55 nm design. AMD has clocked the core frequency at 825 MHz. The GDDR3 RAM is set to run at a speed of 900 MHz on this card. It features 320(64x5) SPUs as well as 16 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Theoretically speaking, the Radeon HD 3870 X2 512MB is 100% quicker than the GeForce 9800 GT 512MB in general, due to its higher bandwidth. (explain)
Texel RateThe GeForce 9800 GT 512MB is quite a bit (approximately 27%) better at anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 3870 X2 512MB is a better choice, by a large margin. (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 maximum 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 interface width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount 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 fill rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.