Compare any two graphics cards:
GeForce 8800 GT 512MB vs Radeon HD 4830 512MB
IntroThe GeForce 8800 GT 512MB features a GPU clock speed of 600 MHz, and the 512 MB of GDDR3 memory runs at 900 MHz through a 256-bit bus. It also is comprised of 112 Stream Processors, 56 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 4830 512MB, which uses a 55 nm design. AMD has set the core frequency at 575 MHz. The GDDR3 memory is set to run at a frequency of 900 MHz on this card. It features 640(128x5) SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have the exact same memory bandwidth, so in theory they should have the same performance. (explain)
Texel RateThe GeForce 8800 GT 512MB will be quite a bit (approximately 83%) more effective at anisotropic filtering than the Radeon HD 4830 512MB. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce 8800 GT 512MB is a better choice, but not by far. (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 (counted in megabytes per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The higher the 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 number of texture map elements (texels) that are processed in one second. This number is worked out by multiplying the total amount of texture units of the card by the core clock speed of the chip. The higher the texel rate, the better the graphics 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 maximum amount of pixels the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.