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 is set to run at 1050 MHz through a 256-bit bus. It also is made up of 1120 Stream Processors, 56 TAUs, and 32 Raster Operation Units.
Compare that to the Radeon HD 7770, which uses a 28 nm design. AMD has clocked the core frequency at 1000 MHz. The GDDR5 RAM runs at a speed of 1125 MHz on this model. It features 640 SPUs along with 40 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 6870 should theoretically perform quite a bit faster than the Radeon HD 7770 overall. (explain)
Texel RateThe Radeon HD 6870 will be much (approximately 26%) faster with regards to texture filtering than the Radeon HD 7770. (explain)
Pixel RateThe Radeon HD 6870 should be much (approximately 80%) better at anti-aliasing than the Radeon HD 7770, and capable of handling higher screen resolutions while still performing well. (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 (in units of MB per second) that can be transferred over the external memory interface in one second. It's calculated by multiplying the card's bus width by its memory clock speed. In the case of DDR RAM, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better 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 can be processed in one second. This figure is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.