Compare any two graphics cards:
Radeon HD 6870 vs Radeon HD 7770
IntroThe Radeon HD 6870 has a GPU core speed of 900 MHz, and the 1024 MB of GDDR5 RAM runs at 1050 MHz through a 256-bit bus. It also is made up of 1120 Stream Processors, 56 Texture Address Units, and 32 ROPs.
Compare those specifications to the Radeon HD 7770, which features a clock frequency of 1000 MHz and a GDDR5 memory frequency of 1125 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is made up of 640 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6870 should in theory be a lot faster than the Radeon HD 7770 in general. (explain)
Texel RateThe Radeon HD 6870 is a lot (more or less 26%) better at AF than the Radeon HD 7770. (explain)
Pixel RateThe Radeon HD 6870 will be much (about 80%) faster with regards to AA than the Radeon HD 7770, and will be able to handle higher resolutions better. (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 (measured in megabytes per second) that can be transported past the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory clock speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total texture units by the core clock speed of the chip. The higher the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the most 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 ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.