Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 has a GPU clock speed of 830 MHz, and the 2048 MB of GDDR5 RAM is set to run at 1250 MHz through a 256-bit bus. It also features 1536 Stream Processors, 96 Texture Address Units, and 32 Raster Operation Units.
Compare those specs to the Radeon HD 7970, which comes with GPU core speed of 925 MHz, and 3072 MB of GDDR5 RAM set to run at 1375 MHz through a 384-bit bus. It also is comprised of 2048 SPUs, 128 Texture Address Units, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 6990 should perform much faster than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 is quite a bit (about 35%) faster with regards to AF than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 is much (about 79%) more effective at AA than the Radeon HD 7970, and capable of handling higher resolutions without slowing down too much. (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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 largest amount of information (counted in MB per second) that can be transferred past the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.