Compare any two graphics cards:
Radeon HD 5970 vs Radeon HD 7870
IntroThe Radeon HD 5970 has a GPU core speed of 725 MHz, and the 1024 MB of GDDR5 RAM runs at 1000 MHz through a 256-bit bus. It also features 1600 Stream Processors, 160 TAUs, and 64 ROPs.
Compare all that to the Radeon HD 7870, which features a clock frequency of 1000 MHz and a GDDR5 memory frequency of 1200 MHz. It also makes use of a 256-bit memory bus, and makes use of a 28 nm design. It is comprised of 1280 SPUs, 80 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 5970 should theoretically perform much faster than the Radeon HD 7870 overall. (explain)
Texel RateThe Radeon HD 5970 will be much (approximately 190%) 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 5970 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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
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 information (counted in megabytes per second) that can be transported over the external memory interface in a second. It's worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total number of texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel 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 potential to reach the max fill rate.