Compare any two graphics cards:
GeForce 8800 GT 512MB vs GeForce GTX 780 Ti
IntroThe GeForce 8800 GT 512MB features a GPU clock speed of 600 MHz, and the 512 MB of GDDR3 memory runs at 900 MHz through a 256-bit bus. It also is made up of 112 SPUs, 56 Texture Address Units, and 16 Raster Operation Units.
Compare those specifications to the GeForce GTX 780 Ti, which has a clock frequency of 875 MHz and a GDDR5 memory speed of 1750 MHz. It also makes use of a 384-bit memory bus, and uses a 28 nm design. It is made up of 2880 SPUs, 240 TAUs, and 48 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 780 Ti will be 483% quicker than the GeForce 8800 GT 512MB overall, due to its higher data rate. (explain)
Texel RateThe GeForce GTX 780 Ti should be much (about 525%) better at texture filtering than the GeForce 8800 GT 512MB. (explain)
Pixel RateThe GeForce GTX 780 Ti should be quite a bit (more or less 338%) better at FSAA than the GeForce 8800 GT 512MB, and also will be capable of handling higher 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.
Memory Bandwidth: Memory bandwidth is the largest amount of data (measured in MB per second) that can be transferred over the external memory interface in one second. It's worked out by multiplying the interface width by the speed of its memory. If it uses DDR type RAM, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This number is calculated by multiplying the total amount of texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to get to the max fill rate.