Compare any two graphics cards:
Radeon HD 6770 1GB vs Radeon HD 6870
IntroThe Radeon HD 6770 1GB has a core clock speed of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also makes use of a 128-bit memory bus, and uses a 40 nm design. It is made up of 800 SPUs, 40 TAUs, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 6870, which comes with clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 RAM. It features 1120 SPUs along with 56 Texture Address Units and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 6870 is 100% faster than the Radeon HD 6770 1GB overall, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 6870 should be a lot (more or less 40%) faster with regards to AF than the Radeon HD 6770 1GB. (explain)
Pixel RateIf using a high 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 largest amount of information (in units of MB per second) that can be transported across the external memory interface in a second. It is calculated by multiplying the card's interface width by its memory clock speed. If it uses DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, 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 graphics card could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of ROPs by the the core 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 - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.