Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 uses a 40 nm design. AMD has set the core speed at 830 MHz. The GDDR5 memory runs at a speed of 1250 MHz on this specific model. It features 1536 SPUs as well as 96 Texture Address Units and 32 ROPs.
Compare all of that 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 Stream Processors, 128 TAUs, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6990 should in theory perform a lot faster than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 should be quite a bit (approximately 35%) better at AF than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 is quite a bit (approximately 79%) better at FSAA than the Radeon HD 7970, and also will be capable of handling higher 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: Memory bandwidth is the maximum amount of data (in units of megabytes per second) that can be transported past the external memory interface in a second. It is worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen 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 by the core 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 processed per second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip could possibly write to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the core clock speed. 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 fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.