Compare any two graphics cards:
Radeon HD 6990 vs Radeon HD 7970
IntroThe Radeon HD 6990 features a clock frequency of 830 MHz and a GDDR5 memory frequency of 1250 MHz. It also uses a 256-bit bus, and uses a 40 nm design. It is made up of 1536 SPUs, 96 TAUs, and 32 Raster Operation Units.
Compare those specifications to the Radeon HD 7970, which features GPU clock speed of 925 MHz, and 3072 MB of GDDR5 memory set to run at 1375 MHz through a 384-bit bus. It also is comprised of 2048 SPUs, 128 TAUs, and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6990, in theory, should be much faster than the Radeon HD 7970 in general. (explain)
Texel RateThe Radeon HD 6990 will be a lot (more or less 35%) faster with regards to anisotropic filtering than the Radeon HD 7970. (explain)
Pixel RateThe Radeon HD 6990 will be a lot (approximately 79%) faster with regards to FSAA than the Radeon HD 7970, and should be able to handle higher screen 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.
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 largest amount of data (measured in megabytes per second) that can be transferred past the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type RAM, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total texture units by the core speed of the chip. The better the texel rate, the better the card will be at 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 record to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.