Compare any two graphics cards:
Radeon HD 6850 vs Radeon HD 7770
IntroThe Radeon HD 6850 has a GPU core clock speed of 775 MHz, and the 1024 MB of GDDR5 memory is set to run at 1000 MHz through a 256-bit bus. It also features 960 SPUs, 48 Texture Address Units, and 32 ROPs.
Compare that to the Radeon HD 7770, which has a core clock frequency of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also makes use of a 128-bit bus, and uses a 28 nm design. It features 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6850 is 78% quicker than the Radeon HD 7770 in general, due to its higher bandwidth. (explain)
Texel RateThe Radeon HD 7770 will be a small bit (more or less 8%) more effective at AF than the Radeon HD 6850. (explain)
Pixel RateIf using 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 information (measured in MB per second) that can be moved past the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR RAM, it should be multiplied by 2 once 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 high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the 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 most pixels that the graphics card can possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on quite a few other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.