Compare any two graphics cards:
GeForce GTX 580 vs Radeon HD 4850 512MB
IntroThe GeForce GTX 580 features a GPU core clock speed of 772 MHz, and the 1536 MB of GDDR5 memory runs at 1002 MHz through a 384-bit bus. It also features 512 SPUs, 64 TAUs, and 48 ROPs.
Compare that to the Radeon HD 4850 512MB, which makes use of a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR3 memory works at a speed of 993 MHz on this card. It features 800(160x5) SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 580 will be 203% faster than the Radeon HD 4850 512MB in general, because of its greater bandwidth. (explain)
Texel RateThe GeForce GTX 580 should be quite a bit (approximately 98%) better at anisotropic filtering than the Radeon HD 4850 512MB. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce GTX 580 is superior to the Radeon HD 4850 512MB, by a large margin. (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.
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 (measured in megabytes per second) that can be transferred over the external memory interface in a second. The number is calculated by multiplying the interface width by its memory speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, 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 are applied in one second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.