Compare any two graphics cards:
GeForce 9800 GX2 vs Radeon HD 4870 512MB
IntroThe GeForce 9800 GX2 makes use of a 65 nm design. nVidia has clocked the core frequency at 600 MHz. The GDDR3 memory is set to run at a frequency of 1000 MHz on this particular model. It features 128 SPUs along with 64 TAUs and 16 ROPs.
Compare that to the Radeon HD 4870 512MB, which comes with a core clock frequency of 750 MHz and a GDDR5 memory frequency of 900 MHz. It also makes use of a 256-bit bus, and makes use of a 55 nm design. It features 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the GeForce 9800 GX2 should in theory be a small bit better than the Radeon HD 4870 512MB overall. (explain)
Texel RateThe GeForce 9800 GX2 is much (more or less 156%) faster with regards to AF than the Radeon HD 4870 512MB. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the GeForce 9800 GX2 is a better choice, by a large margin. (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.
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: Bandwidth is the max amount of information (in units of megabytes per second) that can be transferred over the external memory interface in a second. It's worked out by multiplying the interface width by its memory speed. If the card has DDR RAM, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total texture units of the card by the core clock 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 a second.
Pixel Rate: Pixel rate is the most pixels the video card could possibly record to the local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Render Output Units by the the core speed of the card. 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 - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.