Compare any two graphics cards:
GeForce GTX 280 vs Radeon HD 3870 X2 1GB
IntroThe GeForce GTX 280 features a clock speed of 602 MHz and a GDDR3 memory frequency of 1107 MHz. It also features a 512-bit memory bus, and makes use of a 65 nm design. It features 240 SPUs, 80 TAUs, and 32 ROPs.
Compare those specifications to the Radeon HD 3870 X2 1GB, which features core clock speeds of 825 MHz on the GPU, and 1126 MHz on the 1024 MB of GDDR4 RAM. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 ROPs.
Power Usage and Theoretical Benchmarks
The Radeon HD 3870 X2 1GB should in theory be a little bit faster than the GeForce GTX 280 in general. (explain)
Texel RateThe GeForce GTX 280 should be much (about 82%) better at anisotropic filtering than the Radeon HD 3870 X2 1GB. (explain)
Pixel RateThe Radeon HD 3870 X2 1GB should be quite a bit (more or less 37%) better at full screen anti-aliasing than the GeForce GTX 280, and capable of handling higher resolutions more effectively. (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 maximum amount of data (counted in megabytes per second) that can be moved past the external memory interface in a second. It's calculated by multiplying the bus width by its memory speed. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the video 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 maximum number of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. 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 of the card - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.