Compare any two graphics cards:
GeForce 9400 GT 256MB vs GeForce 9800 GX2
IntroThe GeForce 9400 GT 256MB has a GPU core clock speed of 550 MHz, and the 256 MB of GDDR2 RAM is set to run at 400 MHz through a 128-bit bus. It also is comprised of 16 Stream Processors, 8 Texture Address Units, and 4 Raster Operation Units.
Compare that to the GeForce 9800 GX2, which makes use of a 65 nm design. nVidia has clocked the core speed at 600 MHz. The GDDR3 RAM works at a speed of 1000 MHz on this card. It features 128 SPUs as well as 64 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the GeForce 9800 GX2 should theoretically be quite a bit superior to the GeForce 9400 GT 256MB in general. (explain)
Texel RateThe GeForce 9800 GX2 will be much (approximately 1645%) more effective at anisotropic filtering than the GeForce 9400 GT 256MB. (explain)
Pixel RateThe GeForce 9800 GX2 is a lot (approximately 773%) faster with regards to FSAA than the GeForce 9400 GT 256MB, and should be capable of handling higher resolutions without slowing down too much. (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 maximum amount of information (counted in megabytes per second) that can be moved across the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the 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 amount of texture map elements (texels) that can be processed per second. This is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly record to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.