Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 has a core clock speed of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also features a 256-bit bus, and uses a 40 nm design. It is comprised of 1536 SPUs, 96 TAUs, and 32 ROPs.
Compare all that to the Radeon HD 7970, which uses a 28 nm design. AMD has set the core speed at 925 MHz. The GDDR5 memory runs at a frequency of 1375 MHz on this particular card. It features 2048 SPUs as well as 128 Texture Address Units and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the Radeon HD 6990 should in theory be a lot superior to the Radeon HD 7970 in general. (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 should be quite a bit (more or less 79%) better at anti-aliasing than the Radeon HD 7970, and should be able to handle higher resolutions better. (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 maximum amount of data (measured in MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the interface width by the speed of its memory. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better 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 texture map elements (texels) that can be processed per second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the 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 record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines 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 output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.