Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 comes with core speeds of 830 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 RAM. It features 1536 SPUs as well as 96 TAUs and 32 Rasterization Operator Units.
Compare all that to the Radeon HD 7970, which comes with core clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 memory. It features 2048 SPUs along with 128 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6990 should perform a lot faster than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 is quite a bit (more or less 35%) more effective at texture filtering than the Radeon HD 7970. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 6990 is superior to the Radeon HD 7970, and very much so. (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.
Radeon HD 6990
Radeon HD 7970
Memory Bandwidth: Memory bandwidth is the largest amount of data (counted in megabytes per second) that can be transported across the external memory interface within a second. The number is calculated by multiplying the interface width by its memory speed. In the case of DDR type memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total amount of texture units by the core speed of the chip. The better this number, the better the graphics card will be at handling 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 the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.
Radeon HD 6990
Radeon HD 7970