Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 features a GPU core 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 is made up of 1536 Stream Processors, 96 TAUs, and 32 Raster Operation Units.
Compare those specs to the Radeon HD 7970, which comes with a clock frequency of 925 MHz and a GDDR5 memory speed of 1375 MHz. It also uses a 384-bit memory bus, and makes use of a 28 nm design. It is comprised of 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 6990 should theoretically be a lot better than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 is much (more or less 35%) faster with regards to AF than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 is quite a bit (about 79%) better at AA than the Radeon HD 7970, and also capable of handling higher resolutions while still performing well. (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: Bandwidth is the largest amount of data (measured in MB per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the bus width by its memory clock speed. In the case of DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the 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 number of pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.