Compare any two graphics cards:
Radeon HD 4850 X2 1GB vs Radeon HD 5970
IntroThe Radeon HD 4850 X2 1GB comes with a GPU clock speed of 625 MHz, and the 1024 MB of GDDR3 RAM runs at 993 MHz through a 256-bit bus. It also features 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 5970, which comes with a core clock speed of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also features a 256-bit memory bus, and makes use of a 40 nm design. It is made up of 1600 SPUs, 160 Texture Address Units, and 64 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 5970 should theoretically be much faster than the Radeon HD 4850 X2 1GB in general. (explain)
Texel RateThe Radeon HD 5970 should be quite a bit (about 364%) faster with regards to anisotropic filtering than the Radeon HD 4850 X2 1GB. (explain)
Pixel RateThe Radeon HD 5970 should be quite a bit (about 364%) better at anti-aliasing than the Radeon HD 4850 X2 1GB, 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.
One or more cards in this comparison are multi-core. This means that their bandwidth, texel and pixel rates are theoretically doubled - this does not mean the card will actually perform twice as fast, but only that it should in theory be able to. Actual game benchmarks will give a more accurate idea of what it's capable of.
Memory Bandwidth: Memory bandwidth is the maximum amount of information (measured in MB per second) that can be transferred past the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. If the card has DDR RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Raster Operations Pipelines by the the core 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 fill rate also depends on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.