Compare any two graphics cards:
Radeon HD 6770 vs Radeon HD 6850
IntroThe Radeon HD 6770 has core speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 RAM. It features 800 SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.
Compare all of that to the Radeon HD 6850, which has a core clock frequency of 775 MHz and a GDDR5 memory speed of 1000 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It features 960 SPUs, 48 TAUs, and 32 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 6850 should be 90% quicker than the Radeon HD 6770 in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 6850 is just a bit (more or less 3%) faster with regards to AF than the Radeon HD 6770. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the Radeon HD 6850 is the winner, by a large margin. (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 max amount of data (counted in megabytes per second) that can be transported across the external memory interface in one second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the 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 can possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.