Compare any two graphics cards:
GeForce 9800 GX2 vs Radeon HD 3470 512MB
IntroThe GeForce 9800 GX2 comes with a core clock frequency of 600 MHz and a GDDR3 memory speed of 1000 MHz. It also uses a 256-bit memory bus, and uses a 65 nm design. It is comprised of 128 SPUs, 64 Texture Address Units, and 16 Raster Operation Units.
Compare all of that to the Radeon HD 3470 512MB, which comes with a core clock frequency of 800 MHz and a GDDR3 memory speed of 950 MHz. It also features a 128-bit memory bus, and makes use of a 55 nm design. It is made up of 40(8x5) SPUs, 4 TAUs, and 4 ROPs.
Power Usage and Theoretical Benchmarks
The GeForce 9800 GX2, in theory, should be quite a bit faster than the Radeon HD 3470 512MB in general. (explain)
Texel RateThe GeForce 9800 GX2 will be a lot (approximately 2300%) more effective at AF than the Radeon HD 3470 512MB. (explain)
Pixel RateThe GeForce 9800 GX2 will be much (approximately 500%) faster with regards to full screen anti-aliasing than the Radeon HD 3470 512MB, and also able to handle higher screen resolutions while still performing well. (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 max amount of data (in units of MB per second) that can be transported over the external memory interface in a second. The number is worked out by multiplying the interface width by its memory speed. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This is worked out by multiplying the total texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to its local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.