Compare any two graphics cards:
Radeon HD 6770 vs Radeon HD 6870
IntroThe Radeon HD 6770 features a GPU clock speed of 900 MHz, and the 512 MB of GDDR5 memory is set to run at 1050 MHz through a 128-bit bus. It also features 800 SPUs, 40 TAUs, and 16 ROPs.
Compare all that to the Radeon HD 6870, which comes with core 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 TAUs and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6870 is 100% quicker than the Radeon HD 6770 in general, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 6870 is a lot (more or less 40%) better at texture filtering than the Radeon HD 6770. (explain)
Pixel RateThe Radeon HD 6870 is quite a bit (more or less 100%) faster with regards to AA than the Radeon HD 6770, and also able to handle 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 data (in units of megabytes per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied 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 this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to the local memory per second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on many other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.