Compare any two graphics cards:
GeForce GTX 660 vs Radeon HD 7770
IntroThe GeForce GTX 660 has a GPU core clock speed of 980 MHz, and the 2048 MB of GDDR5 RAM runs at 1502 MHz through a 192-bit bus. It also is made up of 960 Stream Processors, 80 TAUs, and 24 ROPs.
Compare that to the Radeon HD 7770, which makes use of a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM runs at a speed of 1125 MHz on this specific model. It features 640 SPUs along with 40 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 660 will be 100% quicker than the Radeon HD 7770 in general, due to its higher bandwidth. (explain)
Texel RateThe GeForce GTX 660 should be quite a bit (more or less 96%) better at anisotropic filtering than the Radeon HD 7770. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the GeForce GTX 660 is the winner, 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 (measured in megabytes per second) that can be moved over the external memory interface within a second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR type RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed per second. This is calculated by multiplying the total number of texture units of the card 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 per second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.