Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 uses a 40 nm design. AMD has clocked the core speed at 830 MHz. The GDDR5 memory works at a frequency of 1250 MHz on this specific card. It features 1536 SPUs along with 96 TAUs and 32 ROPs.
Compare all of that to the Radeon HD 7970, which uses a 28 nm design. AMD has clocked the core frequency at 925 MHz. The GDDR5 RAM works at a frequency of 1375 MHz on this specific card. It features 2048 SPUs as well as 128 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 6990 should in theory be quite a bit superior to the Radeon HD 7970 overall. (explain)
Texel RateThe Radeon HD 6990 will be much (about 35%) better at AF than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 is much (about 79%) more effective at FSAA than the Radeon HD 7970, and will 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.
Radeon HD 6990
Radeon HD 7970
Memory Bandwidth: Bandwidth is the max amount of data (in units of megabytes per second) that can be transferred past the external memory interface in a second. It's calculated by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once 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 high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.
Radeon HD 6990
Radeon HD 7970