Compare any two graphics cards:
GeForce GT 430 vs GeForce GT 640 DDR3
IntroThe GeForce GT 430 has clock speeds of 700 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 96 SPUs along with 16 Texture Address Units and 4 ROPs.
Compare that to the GeForce GT 640 DDR3, which comes with a clock frequency of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also makes use of a 128-bit memory bus, and uses a 28 nm design. It is comprised of 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GT 640 DDR3 will be 98% quicker than the GeForce GT 430 overall, due to its greater data rate. (explain)
Texel RateThe GeForce GT 640 DDR3 will be much (more or less 157%) more effective at AF than the GeForce GT 430. (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: Memory bandwidth is the max amount of data (in units of MB per second) that can be moved past the external memory interface in one second. It is worked out by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is calculated by multiplying the total amount of texture units of the card by the core 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 processed in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - also called 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, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.