Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650
IntroThe GeForce GT 640 DDR3 comes with clock speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 memory. It features 384 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.
Compare all that to the GeForce GTX 650, which comes with clock speeds of 1058 MHz on the GPU, and 1250 MHz on the 2048 MB of GDDR5 memory. It features 384 SPUs as well as 32 TAUs and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GTX 650, in theory, should perform a lot faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce GTX 650 is just a bit (about 18%) better at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GTX 650 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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the interface width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the 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 processed in one second. This figure is worked out by multiplying the total texture units by the core speed of the chip. The better this number, 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 maximum number of pixels that the graphics card can possibly write to the local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of colour ROPs by the the core speed of the card. ROPs (Raster Operations Pipelines - also 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 - the lower the memory bandwidth is, the lower the ability to get to the maximum fill rate.