Compare any two graphics cards:
GeForce 8800 GTS (G92) vs GeForce GT 640 DDR3
IntroThe GeForce 8800 GTS (G92) uses a 65 nm design. nVidia has clocked the core frequency at 650 MHz. The GDDR3 RAM works at a speed of 970 MHz on this particular card. It features 128 SPUs along with 64 Texture Address Units and 16 ROPs.
Compare those specifications to the GeForce GT 640 DDR3, which comes with core speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 RAM. It features 384 SPUs along with 32 TAUs and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce 8800 GTS (G92), in theory, should perform a little bit faster than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe GeForce 8800 GTS (G92) will be much (more or less 44%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with high levels of AA is important to you, then the GeForce GT 640 DDR3 is the winner, 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: Bandwidth is the largest amount of data (counted in MB per second) that can be moved over the external memory interface in a second. It's calculated by multiplying the interface width by its memory clock speed. In the case of DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total texture units of the card 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 processed in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of ROPs by the the core clock speed. 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 lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.