Compare any two graphics cards:
Radeon HD 6790 vs Radeon HD 6870
IntroThe Radeon HD 6790 uses a 40 nm design. AMD has clocked the core frequency at 840 MHz. The GDDR5 RAM runs at a frequency of 1050 MHz on this specific model. It features 800 SPUs along with 40 TAUs and 16 ROPs.
Compare all of that to the Radeon HD 6870, which comes with a clock speed of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also uses a 256-bit memory bus, and uses a 40 nm design. It is made up of 1120 SPUs, 56 Texture Address Units, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so in theory they should have identical performance. (explain)
Texel RateThe Radeon HD 6870 should be quite a bit (more or less 50%) better at anisotropic filtering than the Radeon HD 6790. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 6870 is superior to the Radeon HD 6790, by a large margin. (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.
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 max amount of information (in units of megabytes per second) that can be moved across the external memory interface within a second. It's worked out by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the card's 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 texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per 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. The figure is worked out by multiplying the amount of Raster Operations Pipelines 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 fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.