Compare any two graphics cards:
Radeon HD 6790 vs Radeon HD 7950
IntroThe Radeon HD 6790 features a GPU clock speed of 840 MHz, and the 1024 MB of GDDR5 memory is set to run at 1050 MHz through a 256-bit bus. It also features 800 SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 7950, which features a clock frequency of 800 MHz and a GDDR5 memory speed of 1250 MHz. It also makes use of a 384-bit memory bus, and makes use of a 28 nm design. It is made up of 1792 SPUs, 112 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 7950 is 79% quicker than the Radeon HD 6790 in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 7950 should be much (about 167%) more effective at texture filtering than the Radeon HD 6790. (explain)
Pixel RateThe Radeon HD 7950 will be a lot (about 90%) better at anti-aliasing than the Radeon HD 6790, and should be capable of handling 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: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transported over the external memory interface within a second. It is calculated by multiplying the interface width by the speed of its memory. In the case of DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be applied per second. This number is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.