Compare any two graphics cards:
Radeon HD 6950 vs Radeon HD 7950
IntroThe Radeon HD 6950 features a clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also uses a 256-bit bus, and uses a 40 nm design. It is made up of 1408 SPUs, 88 TAUs, and 32 ROPs.
Compare that to the Radeon HD 7950, which uses a 28 nm design. AMD has set the core speed at 800 MHz. The GDDR5 memory works at a speed of 1250 MHz on this particular card. It features 1792 SPUs along with 112 TAUs and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
In theory, the Radeon HD 7950 should be 50% faster than the Radeon HD 6950 overall, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7950 is quite a bit (more or less 27%) faster with regards to AF than the Radeon HD 6950. (explain)
Pixel RateBoth cards have exactly the same pixel fill rate, so in theory they should perform equally good at at anti-aliasing, and be capable of handling the same screen resolutions. (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 information (in units of MB per second) that can be transferred past the external memory interface in one second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, the result should 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 higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is worked out by multiplying the total texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate also depends on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.