Compare any two graphics cards:
GeForce 8800 GTS (G92) vs GeForce GT 640 DDR3
IntroThe GeForce 8800 GTS (G92) has a GPU core speed of 650 MHz, and the 512 MB of GDDR3 memory is set to run at 970 MHz through a 256-bit bus. It also is made up of 128 SPUs, 64 Texture Address Units, and 16 ROPs.
Compare all of that to the GeForce GT 640 DDR3, which features a GPU core clock speed of 900 MHz, and 2048 MB of DDR3 memory set to run at 1782 MHz through a 128-bit bus. It also is made up of 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce 8800 GTS (G92) should in theory perform just a bit faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce 8800 GTS (G92) should be quite a bit (approximately 44%) better at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe GeForce GT 640 DDR3 is quite a bit (about 38%) more effective at FSAA than the GeForce 8800 GTS (G92), and also will be capable of handling higher screen 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.
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 (measured in MB per second) that can be transferred over the external memory interface within a second. It is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR type RAM, it should be multiplied by 2 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, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are 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 this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip can possibly write to its local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel output rate is also dependant on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.