Compare any two graphics cards:
Radeon HD 5870 vs Radeon HD 7970
IntroThe Radeon HD 5870 has core clock speeds of 850 MHz on the GPU, and 1200 MHz on the 1024 MB of GDDR5 memory. It features 1600(320x5) SPUs as well as 80 TAUs and 32 ROPs.
Compare that to the Radeon HD 7970, which comes with clock speeds of 925 MHz on the GPU, and 1375 MHz on the 3072 MB of GDDR5 RAM. It features 2048 SPUs along with 128 TAUs and 32 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 7970 should theoretically perform much faster than the Radeon HD 5870 overall. (explain)
Texel RateThe Radeon HD 7970 will be quite a bit (approximately 74%) more effective at anisotropic filtering than the Radeon HD 5870. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 7970 is the winner, not by a very large margin though. (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: Bandwidth is the largest amount of data (in units of MB per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total number of texture units by the core speed of the chip. The better this number, the better the 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 can possibly record to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units 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 rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.