Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650 Ti 2GB
IntroThe GeForce GT 640 DDR3 makes use of a 28 nm design. nVidia has set the core frequency at 900 MHz. The DDR3 RAM works at a frequency of 1782 MHz on this card. It features 384 SPUs as well as 32 Texture Address Units and 16 Rasterization Operator Units.
Compare all that to the GeForce GTX 650 Ti 2GB, which features GPU clock speed of 928 MHz, and 2048 MB of GDDR5 memory set to run at 1350 MHz through a 128-bit bus. It also is made up of 768 SPUs, 64 Texture Address Units, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
As far as performance goes, the GeForce GTX 650 Ti 2GB should in theory be much better than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce GTX 650 Ti 2GB should be much (more or less 106%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateThe GeForce GTX 650 Ti 2GB is just a bit (more or less 3%) better at AA than the GeForce GT 640 DDR3, and also should be able to handle higher screen resolutions more effectively. (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 maximum amount of data (in units of MB per second) that can be moved across the external memory interface in a second. It's calculated by multiplying the interface width by its memory speed. In the case of DDR RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by 4 instead. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that can be processed per second. This is calculated 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 graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the number of colour ROPs by the clock 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 output rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.