Compare any two graphics cards:
Radeon HD 6770 vs Radeon HD 6870
IntroThe Radeon HD 6770 has core clock speeds of 900 MHz on the GPU, and 1050 MHz on the 512 MB of GDDR5 memory. It features 800 SPUs along with 40 Texture Address Units and 16 Rasterization Operator Units.
Compare all that to the Radeon HD 6870, which features core clock speeds of 900 MHz on the GPU, and 1050 MHz on the 1024 MB of GDDR5 memory. It features 1120 SPUs as well as 56 Texture Address Units and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6870 is 100% faster than the Radeon HD 6770 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 6870 should be much (approximately 40%) better at texture filtering than the Radeon HD 6770. (explain)
Pixel RateIf running with high levels of AA is important to you, then the Radeon HD 6870 is superior to the Radeon HD 6770, 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: Memory bandwidth is the max amount of data (counted in MB per second) that can be transferred over the external memory interface in one second. It is calculated by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher 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 number of texture map elements (texels) that can be processed in one second. This figure is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate 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 also depends 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.