Compare any two graphics cards:
GeForce 9800 GTX+ vs Radeon HD 3870 X2 512MB
IntroThe GeForce 9800 GTX+ features a clock speed of 738 MHz and a GDDR3 memory speed of 1100 MHz. It also makes use of a 256-bit bus, and makes use of a 55 nm design. It features 128 SPUs, 64 Texture Address Units, and 16 ROPs.
Compare those specs to the Radeon HD 3870 X2 512MB, which comes with core clock speeds of 825 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 320(64x5) SPUs as well as 16 Texture Address Units and 16 ROPs.
Power Usage and Theoretical Benchmarks
In theory, the Radeon HD 3870 X2 512MB should perform a lot faster than the GeForce 9800 GTX+ overall. (explain)
Texel RateThe GeForce 9800 GTX+ will be much (more or less 79%) faster with regards to texture filtering than the Radeon HD 3870 X2 512MB. (explain)
Pixel RateThe Radeon HD 3870 X2 512MB should be quite a bit (approximately 124%) more effective at full screen anti-aliasing than the GeForce 9800 GTX+, and also should be able to handle higher resolutions better. (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 megabytes per second) that can be transported across the external memory interface in a second. It is worked out by multiplying the bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.