Compare any two graphics cards:
Radeon HD 6870 vs Radeon HD 7790
IntroThe Radeon HD 6870 uses a 40 nm design. AMD has set the core frequency at 900 MHz. The GDDR5 memory runs at a frequency of 1050 MHz on this card. It features 1120 SPUs as well as 56 TAUs and 32 Rasterization Operator Units.
Compare those specs to the Radeon HD 7790, which features a core clock speed of 1000 MHz and a GDDR5 memory frequency of 1500 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It is made up of 896 SPUs, 56 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 6870 is 40% faster than the Radeon HD 7790 overall, because of its greater bandwidth. (explain)
Texel RateThe Radeon HD 7790 should be a little bit (approximately 11%) better at AF than the Radeon HD 6870. (explain)
Pixel RateIf using a high screen resolution is important to you, then the Radeon HD 6870 is the winner, 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 maximum amount of data (counted in megabytes per second) that can be transferred across the external memory interface in one second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the better 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 number of texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The higher this number, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics 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 number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.