Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 comes with a clock speed of 830 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It features 1536 SPUs, 96 TAUs, and 32 Raster Operation Units.
Compare those specifications to the Radeon HD 7970, which comes with GPU core speed of 925 MHz, and 3072 MB of GDDR5 RAM running at 1375 MHz through a 384-bit bus. It also is made up of 2048 SPUs, 128 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6990 should in theory perform quite a bit faster than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 is a lot (approximately 35%) faster with regards to anisotropic filtering than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 is much (more or less 79%) faster with regards to AA than the Radeon HD 7970, and should be able to handle higher screen 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: Bandwidth is the largest amount of data (in units of MB per second) that can be moved past the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total texture units by the core speed of the chip. The higher this number, the better the 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 maximum number of pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.