Compare any two graphics cards:
GeForce 8800 GTS (G80) 640MB vs Radeon HD 5830
IntroThe GeForce 8800 GTS (G80) 640MB comes with a GPU core clock speed of 513 MHz, and the 640 MB of GDDR3 memory runs at 792 MHz through a 320-bit bus. It also is made up of 96 SPUs, 48 TAUs, and 20 ROPs.
Compare all that to the Radeon HD 5830, which has a clock frequency of 800 MHz and a GDDR5 memory speed of 1000 MHz. It also uses a 256-bit bus, and makes use of a 40 nm design. It is comprised of 1120(224x5) SPUs, 56 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 5830 will be 102% faster than the GeForce 8800 GTS (G80) 640MB in general, because of its higher bandwidth. (explain)
Texel RateThe Radeon HD 5830 will be quite a bit (approximately 82%) faster with regards to anisotropic filtering than the GeForce 8800 GTS (G80) 640MB. (explain)
Pixel RateIf using a high screen resolution is important to you, then the Radeon HD 5830 is the winner, and very much so. (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 largest amount of data (counted in MB per second) that can be transferred over the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the most pixels that the graphics card could 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 ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.