Compare any two graphics cards:
GeForce 9800 GX2 vs Radeon HD 4870 2GB
IntroThe GeForce 9800 GX2 comes with a GPU core speed of 600 MHz, and the 512 MB of GDDR3 RAM is set to run at 1000 MHz through a 256-bit bus. It also is made up of 128 Stream Processors, 64 TAUs, and 16 Raster Operation Units.
Compare all of that to the Radeon HD 4870 2GB, which has GPU clock speed of 750 MHz, and 2048 MB of GDDR5 memory running at 900 MHz through a 256-bit bus. It also is comprised of 800(160x5) SPUs, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce 9800 GX2 will be 11% faster than the Radeon HD 4870 2GB in general, due to its higher data rate. (explain)
Texel RateThe GeForce 9800 GX2 is much (about 156%) better at texture filtering than the Radeon HD 4870 2GB. (explain)
Pixel RateThe GeForce 9800 GX2 should be much (about 60%) more effective at FSAA than the Radeon HD 4870 2GB, and capable of handling higher 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.
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 (measured in megabytes per second) that can be moved past the external memory interface in a second. It is worked out by multiplying the card's bus width by the speed of its memory. In the case of DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster 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 figure is calculated by multiplying the total amount of texture units of the card by the core clock speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the maximum fill rate.