Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 550 Ti
IntroThe GeForce GT 640 DDR3 features a GPU core clock speed of 900 MHz, and the 2048 MB of DDR3 memory runs at 1782 MHz through a 128-bit bus. It also features 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
Compare those specifications to the GeForce GTX 550 Ti, which makes use of a 40 nm design. nVidia has set the core speed at 900 MHz. The GDDR5 memory works at a frequency of 1026 MHz on this card. It features 192 SPUs as well as 32 TAUs and 24 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 550 Ti should perform quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateBoth cards have the exact same texel fill rate, so in theory they should be equally good at at anisotropic filtering. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GTX 550 Ti is superior to the GeForce GT 640 DDR3, 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 maximum amount of information (counted in MB per second) that can be transported across the external memory interface in one second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, the result should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's 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 texture map elements (texels) that are applied per second. This figure is calculated by multiplying the total amount of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card can possibly record to its local memory in a second - measured in millions of pixels per second. The figure is calculated by multiplying the amount of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.