Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 660 Ti
IntroThe GeForce GT 640 DDR3 uses a 28 nm design. nVidia has clocked the core frequency at 900 MHz. The DDR3 RAM runs at a speed of 1782 MHz on this specific card. It features 384 SPUs along with 32 TAUs and 16 Rasterization Operator Units.
Compare those specs to the GeForce GTX 660 Ti, which features a clock speed of 915 MHz and a GDDR5 memory frequency of 1500 MHz. It also features a 192-bit bus, and makes use of a 28 nm design. It is made up of 1344 SPUs, 112 TAUs, and 24 Raster Operation Units.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GTX 660 Ti should in theory be quite a bit faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce GTX 660 Ti will be a lot (approximately 256%) more effective at texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with lots of anti-aliasing is important to you, then the GeForce GTX 660 Ti is the winner, and very much so. (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.
Price ComparisonPlease note that the price comparisons are based on search keywords, and might not be the exact same card listed on this page. We have no control over the accuracy of their search results.
Memory Bandwidth: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be transported past the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 again. If it uses 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, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total number of texture units by the core clock speed of the chip. The better the texel rate, the better the card will be at handling 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 that the graphics chip can possibly record to the local memory in one 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 - sometimes also referred to as Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate is also dependant on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to reach the max fill rate.