Compare any two graphics cards:
GeForce GTS 250 1GB vs Radeon HD 3870 X2 512MB
IntroThe GeForce GTS 250 1GB makes use of a 65/55 nm design. nVidia has clocked the core frequency at 738 MHz. The GDDR3 memory is set to run at a frequency of 1100 MHz on this specific card. It features 128 SPUs as well as 64 Texture Address Units and 16 Rasterization Operator Units.
Compare those specifications to the Radeon HD 3870 X2 512MB, which uses a 55 nm design. AMD has set the core frequency at 825 MHz. The GDDR3 memory runs at a speed of 900 MHz on this specific model. It features 320(64x5) SPUs along with 16 Texture Address Units and 16 ROPs.
Power Usage and Theoretical Benchmarks
In theory, the Radeon HD 3870 X2 512MB should be 64% faster than the GeForce GTS 250 1GB in general, because of its higher data rate. (explain)
Texel RateThe GeForce GTS 250 1GB is much (approximately 79%) more effective at texture filtering than the Radeon HD 3870 X2 512MB. (explain)
Pixel RateIf using a high screen resolution is important to you, then the Radeon HD 3870 X2 512MB is superior to the GeForce GTS 250 1GB, and very much so. (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 information (in units of megabytes per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better 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 can be applied per second. This figure is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.