Compare any two graphics cards:
GeForce 8500 GT vs GeForce GT 640 DDR3
IntroThe GeForce 8500 GT has a core clock frequency of 450 MHz and a DDR2 memory speed of 400 MHz. It also uses a 128-bit bus, and uses a 80 nm design. It is made up of 16 SPUs, 8 TAUs, and 4 Raster Operation Units.
Compare that to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 memory works at a frequency of 1782 MHz on this particular card. It features 384 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GT 640 DDR3, in theory, should be a lot faster than the GeForce 8500 GT overall. (explain)
Texel RateThe GeForce GT 640 DDR3 is a lot (approximately 700%) better at AF than the GeForce 8500 GT. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the GeForce GT 640 DDR3 is a better choice, by far. (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 largest amount of information (counted in MB per second) that can be moved past the external memory interface in a second. The number is calculated by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it must be multiplied by 2 again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is calculated by multiplying the total texture units 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 in one second.
Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of ROPs by the the core clock speed. 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 rate is also dependant on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.