Compare any two graphics cards:
GeForce GTX 280 vs Radeon HD 7950
IntroThe GeForce GTX 280 has a GPU clock speed of 602 MHz, and the 1024 MB of GDDR3 memory is set to run at 1107 MHz through a 512-bit bus. It also is comprised of 240 SPUs, 80 TAUs, and 32 ROPs.
Compare those specs to the Radeon HD 7950, which has clock speeds of 800 MHz on the GPU, and 1250 MHz on the 1536 MB of GDDR5 RAM. It features 1792 SPUs along with 112 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7950 is 69% faster than the GeForce GTX 280 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7950 is quite a bit (approximately 86%) more effective at AF than the GeForce GTX 280. (explain)
Pixel RateThe Radeon HD 7950 should be a lot (approximately 33%) better at AA than the GeForce GTX 280, and capable of handling higher resolutions more effectively. (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 data (in units of megabytes per second) that can be transferred past the external memory interface in one second. It is calculated by multiplying the bus width by its memory speed. If it uses DDR type RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The higher this number, the better the graphics 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 the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.