Compare any two graphics cards:
Radeon HD 7870 vs Radeon HD 7970
IntroThe Radeon HD 7870 comes with a GPU core clock speed of 1000 MHz, and the 2048 MB of GDDR5 RAM is set to run at 1200 MHz through a 256-bit bus. It also is made up of 1280 Stream Processors, 80 TAUs, and 32 Raster Operation Units.
Compare that to the Radeon HD 7970, which has a core clock speed of 925 MHz and a GDDR5 memory frequency of 1375 MHz. It also makes use of a 384-bit memory bus, and makes use of a 28 nm design. It is made up of 2048 SPUs, 128 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 7970 should be 72% quicker than the Radeon HD 7870 overall, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 7970 should be a lot (approximately 48%) better at AF than the Radeon HD 7870. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 7870 is the winner, but it probably won't make a huge difference. (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 max amount of information (measured in megabytes per second) that can be transferred over the external memory interface within a second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units by the core clock 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 in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.