Compare any two graphics cards:
GeForce GTX 580 vs Radeon HD 7850
IntroThe GeForce GTX 580 has clock speeds of 772 MHz on the GPU, and 1002 MHz on the 1536 MB of GDDR5 memory. It features 512 SPUs along with 64 TAUs and 48 ROPs.
Compare all that to the Radeon HD 7850, which has a clock speed of 860 MHz and a GDDR5 memory speed of 1200 MHz. It also uses a 256-bit memory bus, and makes use of a 28 nm design. It is comprised of 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 580 should be 25% quicker than the Radeon HD 7850 overall, because of its greater data rate. (explain)
Texel RateThe Radeon HD 7850 is just a bit (more or less 11%) faster with regards to anisotropic filtering than the GeForce GTX 580. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GTX 580 is superior to the Radeon HD 7850, by far. (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: Bandwidth is the max amount of information (measured in MB per second) that can be transported past the external memory interface in a second. The number is calculated by multiplying the card's interface width by its memory speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 can be applied per second. This number is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called 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, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.