Compare any two graphics cards:
Radeon HD 6770 1GB vs Radeon HD 6870
IntroThe Radeon HD 6770 1GB features a clock frequency of 900 MHz and a GDDR5 memory frequency of 1050 MHz. It also makes use of a 128-bit memory bus, and makes use of a 40 nm design. It features 800 SPUs, 40 Texture Address Units, and 16 ROPs.
Compare all that to the Radeon HD 6870, which uses a 40 nm design. AMD has set the core speed at 900 MHz. The GDDR5 memory works at a frequency of 1050 MHz on this card. It features 1120 SPUs along with 56 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the Radeon HD 6870 should in theory be much better than the Radeon HD 6770 1GB overall. (explain)
Texel RateThe Radeon HD 6870 is quite a bit (more or less 40%) better at anisotropic filtering than the Radeon HD 6770 1GB. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the Radeon HD 6870 is a better choice, and very much so. (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 information (counted in megabytes per second) that can be moved past the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory speed. If it uses DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, 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 number is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, 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 maximum amount of pixels the graphics card can possibly write to the local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.