Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650 Ti 2GB
IntroThe GeForce GT 640 DDR3 comes with a GPU core speed of 900 MHz, and the 2048 MB of DDR3 RAM is set to run at 1782 MHz through a 128-bit bus. It also features 384 SPUs, 32 Texture Address Units, and 16 ROPs.
Compare that to the GeForce GTX 650 Ti 2GB, which comes with core clock speeds of 928 MHz on the GPU, and 1350 MHz on the 2048 MB of GDDR5 RAM. It features 768 SPUs along with 64 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 650 Ti 2GB should perform quite a bit faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe GeForce GTX 650 Ti 2GB will be quite a bit (about 106%) more effective at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with a high resolution is important to you, then the GeForce GTX 650 Ti 2GB is a better choice, though not 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: Bandwidth is the largest amount of information (measured in MB per second) that can be moved over the external memory interface in one second. It is calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it should be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better 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 are applied per second. This number is worked out by multiplying the total number of texture units of the card 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 per second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip could possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate is also dependant on many other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to reach the max fill rate.