Compare any two graphics cards:
GeForce GTX 580 3GB vs Radeon HD 7850
IntroThe GeForce GTX 580 3GB has a clock speed of 772 MHz and a GDDR5 memory speed of 1002 MHz. It also features a 384-bit bus, and uses a 40 nm design. It is comprised of 512 SPUs, 64 TAUs, and 48 Raster Operation Units.
Compare those specs to the Radeon HD 7850, which makes use of a 28 nm design. AMD has set the core frequency at 860 MHz. The GDDR5 RAM is set to run at a frequency of 1200 MHz on this card. It features 1024 SPUs as well as 64 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 580 3GB will be 25% faster than the Radeon HD 7850 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7850 will be a bit (more or less 11%) more effective at AF than the GeForce GTX 580 3GB. (explain)
Pixel RateThe GeForce GTX 580 3GB should be quite a bit (about 35%) faster with regards to FSAA than the Radeon HD 7850, and will be capable of handling higher screen resolutions better. (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 maximum amount of information (in units of megabytes per second) that can be transferred over the external memory interface in a second. It is worked out by multiplying the interface width by its memory speed. If the card has DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher the texel rate, the better the video 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 most pixels the graphics card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines 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 rate is also dependant 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.