Compare any two graphics cards:
Radeon HD 6790 vs Radeon HD 6870
IntroThe Radeon HD 6790 has a clock speed of 840 MHz and a GDDR5 memory frequency of 1050 MHz. It also uses a 256-bit bus, and makes use of a 40 nm design. It features 800 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 6870, which has a GPU core clock speed of 900 MHz, and 1024 MB of GDDR5 memory running at 1050 MHz through a 256-bit bus. It also is made up of 1120 Stream Processors, 56 TAUs, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so theoretically they should perform the same. (explain)
Texel RateThe Radeon HD 6870 is a lot (about 50%) more effective at texture filtering than the Radeon HD 6790. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 6870 is the winner, and very much so. (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 maximum amount of data (counted in megabytes per second) that can be moved across the external memory interface within a second. It is worked out by multiplying the bus width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The higher the memory bandwidth, 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 amount of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card could possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.