Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 660 Ti
IntroThe GeForce GT 640 DDR3 has a clock speed of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also makes use of a 128-bit bus, and makes use of a 28 nm design. It features 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
Compare that to the GeForce GTX 660 Ti, which has a clock frequency of 915 MHz and a GDDR5 memory frequency of 1500 MHz. It also features a 192-bit bus, and uses a 28 nm design. It features 1344 SPUs, 112 Texture Address Units, and 24 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 660 Ti should be much faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe GeForce GTX 660 Ti will be much (approximately 256%) better at anisotropic filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateThe GeForce GTX 660 Ti is quite a bit (more or less 53%) faster with regards to anti-aliasing than the GeForce GT 640 DDR3, and 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 max amount of data (measured in megabytes per second) that can be transferred past the external memory interface within a second. The number is calculated by multiplying the card's interface width by its memory speed. If it uses DDR RAM, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's 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 applied in one second. This is calculated by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the most pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs 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 fill 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 potential to get to the max fill rate.