Compare any two graphics cards:
GeForce GT 640 DDR3 vs GeForce GTX 460
IntroThe GeForce GT 640 DDR3 uses a 28 nm design. nVidia has set the core speed at 900 MHz. The DDR3 memory is set to run at a speed of 1782 MHz on this specific model. It features 384 SPUs as well as 32 TAUs and 16 Rasterization Operator Units.
Compare all that to the GeForce GTX 460, which features a clock frequency of 675 MHz and a GDDR5 memory frequency of 900 MHz. It also makes use of a 192-bit bus, and makes use of a 40 nm design. It is comprised of 336 SPUs, 56 TAUs, and 24 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GTX 460 should perform much faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe GeForce GTX 460 will be much (more or less 31%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateThe GeForce GTX 460 should be a bit (approximately 13%) faster with regards to AA than the GeForce GT 640 DDR3, and also will be able to handle higher resolutions better. (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 data (counted in megabytes per second) that can be transported past the external memory interface within a second. It's calculated by multiplying the card's interface width by the speed of its memory. If it uses DDR type RAM, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The better 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 can be applied in one second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The higher the texel rate, the better the 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 most pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.