Compare any two graphics cards:
GeForce 8800 GT 1GB vs GeForce 9600 GT 512MB
IntroThe GeForce 8800 GT 1GB uses a 65 nm design. nVidia has set the core frequency at 600 MHz. The GDDR3 memory runs at a speed of 900 MHz on this specific model. It features 112 SPUs along with 56 Texture Address Units and 16 Rasterization Operator Units.
Compare that to the GeForce 9600 GT 512MB, which comes with core speeds of 650 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 64 SPUs along with 32 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have exactly the same bandwidth, so theoretically they should perform exactly the same. (explain)
Texel RateThe GeForce 8800 GT 1GB is quite a bit (more or less 62%) faster with regards to AF than the GeForce 9600 GT 512MB. (explain)
Pixel RateIf running with a high screen resolution is important to you, then the GeForce 9600 GT 512MB is superior to the GeForce 8800 GT 1GB, 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.
Memory Bandwidth: Bandwidth is the max amount of information (counted in megabytes per second) that can be moved across the external memory interface within a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied in one second. This number is worked out by multiplying the total texture units by the core clock speed of the chip. The better this number, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly write to its local memory in one second - measured in millions of pixels per second. The number is worked out by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.