Compare any two graphics cards:
GeForce 9800 GX2 vs Radeon HD 4870 2GB
IntroThe GeForce 9800 GX2 comes with clock speeds of 600 MHz on the GPU, and 1000 MHz on the 512 MB of GDDR3 memory. It features 128 SPUs along with 64 Texture Address Units and 16 ROPs.
Compare all that to the Radeon HD 4870 2GB, which comes with GPU clock speed of 750 MHz, and 2048 MB of GDDR5 memory running at 900 MHz through a 256-bit bus. It also is made up of 800(160x5) Stream Processors, 40 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce 9800 GX2 should theoretically perform a small bit faster than the Radeon HD 4870 2GB overall. (explain)
Texel RateThe GeForce 9800 GX2 is a lot (about 156%) faster with regards to anisotropic filtering than the Radeon HD 4870 2GB. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce 9800 GX2 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.
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 data (counted in megabytes per second) that can be transported over the external memory interface within a second. It's worked out by multiplying the interface width by the speed of its memory. If the card has DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 amount of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total number of texture units of the card by the core speed of the chip. The better this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card could possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated 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 lots of other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.