Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650 Ti 2GB
IntroThe GeForce GT 640 DDR3 comes with a GPU clock speed of 900 MHz, and the 2048 MB of DDR3 RAM 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 650 Ti 2GB, which has clock speeds of 928 MHz on the GPU, and 1350 MHz on the 2048 MB of GDDR5 RAM. It features 768 SPUs as well as 64 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GTX 650 Ti 2GB should theoretically be a lot faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce GTX 650 Ti 2GB is 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 should be a little bit (about 3%) better at anti-aliasing than the GeForce GT 640 DDR3, and capable of handling higher resolutions while still performing well. (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 max amount of data (measured in megabytes per second) that can be transported over the external memory interface in a second. It is calculated by multiplying the card's bus width by the speed of its memory. If it uses DDR RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The better the bandwidth is, 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 in one second. This figure is calculated by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card can possibly write to its local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the number of colour ROPs by the the card's clock speed. ROPs (Raster Operations Pipelines - also called 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, especially the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the max fill rate.