Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 comes with a GPU core speed of 830 MHz, and the 2048 MB of GDDR5 memory runs at 1250 MHz through a 256-bit bus. It also is made up of 1536 SPUs, 96 TAUs, and 32 Raster Operation Units.
Compare those specs to the Radeon HD 7970, which makes use of a 28 nm design. AMD has clocked the core speed at 925 MHz. The GDDR5 RAM runs at a frequency of 1375 MHz on this particular model. It features 2048 SPUs along with 128 Texture Address Units and 32 Rasterization Operator 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 overall. (explain)
Texel RateThe Radeon HD 6990 is quite a bit (about 35%) more effective at AF than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 will be a lot (more or less 79%) faster with regards to anti-aliasing than the Radeon HD 7970, and also should be able to handle higher screen resolutions more effectively. (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 information (counted in MB per second) that can be moved across the external memory interface in one second. It is worked out by multiplying the card's interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once 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 AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.