Compare any two graphics cards:
Radeon HD 6770 vs Radeon HD 6870
IntroThe Radeon HD 6770 comes with a GPU clock speed of 900 MHz, and the 512 MB of GDDR5 RAM is set to run at 1050 MHz through a 128-bit bus. It also is made up of 800 Stream Processors, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 6870, which has a GPU core clock speed of 900 MHz, and 1024 MB of GDDR5 RAM set to run at 1050 MHz through a 256-bit bus. It also is made up of 1120 Stream Processors, 56 Texture Address Units, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6870 should be 100% faster than the Radeon HD 6770 overall, due to its higher bandwidth. (explain)
Texel RateThe Radeon HD 6870 is a lot (about 40%) better at AF than the Radeon HD 6770. (explain)
Pixel RateThe Radeon HD 6870 will be a lot (about 100%) better at AA than the Radeon HD 6770, and capable of handling higher screen resolutions without slowing down too much. (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 maximum amount of information (measured in megabytes per second) that can be transferred over the external memory interface in one second. The number is worked out by multiplying the card's interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could 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 colour 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 is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.