Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 650
IntroThe GeForce GT 640 DDR3 comes with a clock frequency of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also makes use of a 128-bit bus, and uses a 28 nm design. It is comprised of 384 SPUs, 32 Texture Address Units, and 16 ROPs.
Compare those specs to the GeForce GTX 650, which features a core clock speed of 1058 MHz and a GDDR5 memory speed of 1250 MHz. It also features a 128-bit bus, and makes use of a 28 nm design. It features 384 SPUs, 32 TAUs, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 650 is 40% faster than the GeForce GT 640 DDR3 overall, because of its greater data rate. (explain)
Texel RateThe GeForce GTX 650 will be a little bit (approximately 18%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe GeForce GTX 650 is a little bit (approximately 18%) faster with regards to AA than the GeForce GT 640 DDR3, and capable of handling 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 max amount of data (counted in MB per second) that can be transported across the external memory interface within a second. It is calculated by multiplying the card's interface width by its memory clock speed. In the case of DDR type RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the bandwidth is, the faster 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 worked out by multiplying the total amount of texture units of the card by the core 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 applied in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the video card can possibly record to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on lots of other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.