Compare any two graphics cards:
GeForce GTX 280 vs Radeon HD 3870 X2 1GB
IntroThe GeForce GTX 280 makes use of a 65 nm design. nVidia has clocked the core speed at 602 MHz. The GDDR3 RAM runs at a speed of 1107 MHz on this specific model. It features 240 SPUs as well as 80 Texture Address Units and 32 Rasterization Operator Units.
Compare those specifications to the Radeon HD 3870 X2 1GB, which features a core clock frequency of 825 MHz and a GDDR4 memory speed of 1126 MHz. It also uses a 256-bit bus, and uses a 55 nm design. It features 320(64x5) SPUs, 16 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
The Radeon HD 3870 X2 1GB, in theory, should perform a little bit faster than the GeForce GTX 280 in general. (explain)
Texel RateThe GeForce GTX 280 is much (approximately 82%) more effective at AF than the Radeon HD 3870 X2 1GB. (explain)
Pixel RateThe Radeon HD 3870 X2 1GB will be a lot (about 37%) more effective at full screen anti-aliasing than the GeForce GTX 280, and should be able to handle higher screen resolutions while still performing well. (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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the bus width by its memory clock speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, 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 number of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.