Compare any two graphics cards:
Radeon HD 6870 vs Radeon HD 6950
IntroThe Radeon HD 6870 has a GPU core clock 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 Stream Processors, 56 TAUs, and 32 Raster Operation Units.
Compare those specs to the Radeon HD 6950, which comes with GPU clock speed of 800 MHz, and 1024 MB of GDDR5 memory set to run at 1250 MHz through a 256-bit bus. It also is comprised of 1408 SPUs, 88 TAUs, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 6950 will be 19% faster than the Radeon HD 6870 overall, due to its greater bandwidth. (explain)
Texel RateThe Radeon HD 6950 should be quite a bit (about 40%) more effective at AF than the Radeon HD 6870. (explain)
Pixel RateThe Radeon HD 6870 will be just a bit (more or less 13%) faster with regards to full screen anti-aliasing than the Radeon HD 6950, and should be capable of handling 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 data (counted in MB per second) that can be moved over the external memory interface in a second. It's worked out by multiplying the card's interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, 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 amount of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the video 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 the video card can possibly record to its local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.