Compare any two graphics cards:
GeForce 9800 GTX+ vs Radeon HD 3870 X2 512MB
IntroThe GeForce 9800 GTX+ features core clock speeds of 738 MHz on the GPU, and 1100 MHz on the 512 MB of GDDR3 RAM. It features 128 SPUs as well as 64 TAUs and 16 Rasterization Operator Units.
Compare all of that to the Radeon HD 3870 X2 512MB, which uses a 55 nm design. AMD has clocked the core frequency at 825 MHz. The GDDR3 memory 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
The Radeon HD 3870 X2 512MB should theoretically be quite a bit faster than the GeForce 9800 GTX+ in general. (explain)
Texel RateThe GeForce 9800 GTX+ should be quite a bit (more or less 79%) more effective at anisotropic filtering than the Radeon HD 3870 X2 512MB. (explain)
Pixel RateThe Radeon HD 3870 X2 512MB is much (about 124%) more effective at AA than the GeForce 9800 GTX+, and able to handle higher resolutions without losing too much performance. (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 data (counted in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR memory, it must be multiplied by 2 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, High Dynamic Range and high 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 amount of texture units by the core clock speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.