Compare any two graphics cards:
GeForce 8800 GTS (G92) vs GeForce GT 640 DDR3
IntroThe GeForce 8800 GTS (G92) features a clock frequency of 650 MHz and a GDDR3 memory speed of 970 MHz. It also makes use of a 256-bit memory bus, and makes use of a 65 nm design. It is made up of 128 SPUs, 64 TAUs, and 16 ROPs.
Compare those specs to the GeForce GT 640 DDR3, which comes with a GPU core clock speed of 900 MHz, and 2048 MB of DDR3 RAM set to run at 1782 MHz through a 128-bit bus. It also is made up of 384 Stream Processors, 32 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the GeForce 8800 GTS (G92) should theoretically be just a bit superior to the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce 8800 GTS (G92) is quite a bit (approximately 44%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)
Pixel RateIf using a high screen resolution is important to you, then the GeForce GT 640 DDR3 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.
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 data (counted in megabytes per second) that can be moved past the external memory interface in a second. It is calculated by multiplying the bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly write to its local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.