Compare any two graphics cards:
Radeon HD 6770 1GB vs Radeon HD 6870
IntroThe Radeon HD 6770 1GB comes with a GPU clock speed of 900 MHz, and the 1024 MB of GDDR5 RAM runs at 1050 MHz through a 128-bit bus. It also is comprised of 800 Stream Processors, 40 TAUs, and 16 Raster Operation Units.
Compare all of that to the Radeon HD 6870, which comes with a clock frequency of 900 MHz and a GDDR5 memory speed of 1050 MHz. It also makes use of a 256-bit bus, and uses a 40 nm design. It features 1120 SPUs, 56 Texture Address Units, and 32 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically, the Radeon HD 6870 should perform a lot faster than the Radeon HD 6770 1GB overall. (explain)
Texel RateThe Radeon HD 6870 is quite a bit (more or less 40%) better at texture filtering than the Radeon HD 6770 1GB. (explain)
Pixel RateThe Radeon HD 6870 will be a lot (approximately 100%) faster with regards to anti-aliasing than the Radeon HD 6770 1GB, and also should be capable of handling higher 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 max amount of data (in units of megabytes per second) that can be moved over the external memory interface within a second. It is worked out by multiplying the interface width by its memory speed. In the case of DDR memory, 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 AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed in one second. This number is calculated by multiplying the total 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 texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.