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 comprised of 1120 Stream Processors, 56 Texture Address Units, and 32 Raster Operation Units.
Compare those specifications to the Radeon HD 7770, which makes use of a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM works at a speed of 1125 MHz on this particular model. It features 640 SPUs as well as 40 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6870 is 87% faster than the Radeon HD 7770 in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 6870 should be much (approximately 26%) better at texture filtering than the Radeon HD 7770. (explain)
Pixel RateThe Radeon HD 6870 will be much (approximately 80%) better at anti-aliasing than the Radeon HD 7770, and 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 information (counted in megabytes per second) that can be transferred across 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 memory, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied per second. This is calculated by multiplying the total amount of texture units by the core speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of colour ROPs by the the core speed of the card. 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 many other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the maximum fill rate.