Compare any two graphics cards:
Radeon HD 6790 vs Radeon HD 6870
IntroThe Radeon HD 6790 has core speeds of 840 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 800 SPUs along with 40 TAUs and 16 Rasterization Operator Units.
Compare all of that to the Radeon HD 6870, which features GPU core speed of 900 MHz, and 1024 MB of GDDR5 memory set to run at 1050 MHz through a 256-bit bus. It also is comprised of 1120 Stream Processors, 56 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so theoretically they should have identical performance. (explain)
Texel RateThe Radeon HD 6870 should be much (approximately 50%) faster with regards to texture filtering than the Radeon HD 6790. (explain)
Pixel RateIf using a high screen resolution 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 largest amount of data (counted in megabytes per second) that can be transferred across the external memory interface in a second. It is calculated by multiplying the card's bus width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the most pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.