Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 comes with core clock speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 1536 SPUs as well as 96 TAUs and 32 Rasterization Operator Units.
Compare those specs to the Radeon HD 7970, which has core clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs as well as 128 TAUs and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 6990 should be 21% faster than the Radeon HD 7970 in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 6990 is quite a bit (approximately 35%) faster with regards to anisotropic filtering than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 will be a lot (about 79%) better at anti-aliasing than the Radeon HD 7970, and also should be 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: Memory bandwidth is the max amount of data (measured in MB per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory clock speed. If the card has DDR RAM, it should be multiplied by 2 again. If it uses 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 are applied per second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.