Compare any two graphics cards:
GeForce GTX 580 vs Radeon HD 7850
IntroThe GeForce GTX 580 uses a 40 nm design. nVidia has set the core speed at 772 MHz. The GDDR5 memory is set to run at a speed of 1002 MHz on this particular card. It features 512 SPUs along with 64 Texture Address Units and 48 ROPs.
Compare all that to the Radeon HD 7850, which has clock speeds of 860 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1024 SPUs as well as 64 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 580 should be much faster than the Radeon HD 7850 overall. (explain)
Texel RateThe Radeon HD 7850 is just a bit (about 11%) faster with regards to AF than the GeForce GTX 580. (explain)
Pixel RateIf using a high resolution is important to you, then the GeForce GTX 580 is a better choice, 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: Bandwidth is the largest amount of data (in units of megabytes per second) that can be transported past the external memory interface in a second. It's calculated by multiplying the interface width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.