Compare any two graphics cards:
Radeon HD 7870 vs Radeon HD 7970
IntroThe Radeon HD 7870 has clock speeds of 1000 MHz on the GPU, and 1200 MHz on the 2048 MB of GDDR5 memory. It features 1280 SPUs along with 80 Texture Address Units and 32 Rasterization Operator Units.
Compare all of that to the Radeon HD 7970, which has a clock frequency of 925 MHz and a GDDR5 memory frequency of 1375 MHz. It also features a 384-bit memory bus, and makes use of a 28 nm design. It is comprised of 2048 SPUs, 128 TAUs, 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 higher data rate. (explain)
Texel RateThe Radeon HD 7970 will be much (about 48%) more effective at anisotropic filtering than the Radeon HD 7870. (explain)
Pixel RateThe Radeon HD 7870 should be a small bit (about 8%) more effective at FSAA than the Radeon HD 7970, and also should be capable of handling higher screen resolutions better. (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 information (in units of megabytes per second) that can be transferred over the external memory interface in a second. It is calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR type memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.