Compare any two graphics cards:
Radeon HD 7850 vs Radeon HD 7870
IntroThe Radeon HD 7850 comes with a GPU core speed of 860 MHz, and the 2048 MB of GDDR5 RAM runs at 1200 MHz through a 256-bit bus. It also is made up of 1024 SPUs, 64 Texture Address Units, and 32 ROPs.
Compare those specifications to the Radeon HD 7870, which has core speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 RAM. It features 1280 SPUs as well as 80 Texture Address Units and 32 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have exactly the same bandwidth, so in theory they should have the same performance. (explain)
Texel RateThe Radeon HD 7870 should be a lot (about 45%) faster with regards to texture filtering than the Radeon HD 7850. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 7870 is the winner, though not by far. (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 data (counted in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units by the core 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 processed in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that 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 card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.