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 memory runs at 1050 MHz through a 256-bit bus. It also is made up of 1120 SPUs, 56 TAUs, and 32 Raster Operation Units.
Compare those specifications to the Radeon HD 7770, which comes with GPU core speed of 1000 MHz, and 1024 MB of GDDR5 memory set to run at 1125 MHz through a 128-bit bus. It also is made up of 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 6870 should perform a lot faster than the Radeon HD 7770 overall. (explain)
Texel RateThe Radeon HD 6870 will be much (approximately 26%) faster with regards to AF than the Radeon HD 7770. (explain)
Pixel RateThe Radeon HD 6870 should be a lot (approximately 80%) faster with regards to anti-aliasing than the Radeon HD 7770, and also will be able to handle higher resolutions without losing too much performance. (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 transported past the external memory interface in a second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's 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 applied in one second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly record 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 card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.