Compare any two graphics cards:
Radeon HD 5870 vs Radeon HD 6990
IntroThe Radeon HD 5870 has a clock frequency of 850 MHz and a GDDR5 memory frequency of 1200 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 1600(320x5) SPUs, 80 Texture Address Units, and 32 ROPs.
Compare those specs to the Radeon HD 6990, which uses a 40 nm design. AMD has clocked the core speed at 830 MHz. The GDDR5 RAM runs at a frequency of 1250 MHz on this specific card. It features 1536 SPUs along with 96 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6990 will be 108% faster than the Radeon HD 5870 in general, because of its greater data rate. (explain)
Texel RateThe Radeon HD 6990 will be a lot (about 134%) faster with regards to AF than the Radeon HD 5870. (explain)
Pixel RateThe Radeon HD 6990 should be a lot (approximately 95%) faster with regards to full screen anti-aliasing than the Radeon HD 5870, and will be capable of handling higher 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: Memory bandwidth is the largest amount of data (in units of MB per second) that can be transported over the external memory interface within a second. It's calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This figure is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output 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 reach the max fill rate.