Compare any two graphics cards:
GeForce 9600 GSO 512MB vs GeForce GTS 250 1GB
IntroThe GeForce 9600 GSO 512MB features core clock speeds of 650 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 96 SPUs as well as 48 TAUs and 16 Rasterization Operator Units.
Compare all that to the GeForce GTS 250 1GB, which comes with GPU clock speed of 738 MHz, and 1024 MB of GDDR3 RAM set to run at 1100 MHz through a 256-bit bus. It also features 128 Stream Processors, 64 Texture Address Units, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GTS 250 1GB should in theory be a lot faster than the GeForce 9600 GSO 512MB overall. (explain)
Texel RateThe GeForce GTS 250 1GB will be a lot (about 51%) faster with regards to anisotropic filtering than the GeForce 9600 GSO 512MB. (explain)
Pixel RateThe GeForce GTS 250 1GB will be a little bit (more or less 14%) better at anti-aliasing than the GeForce 9600 GSO 512MB, and will be able to handle higher screen resolutions without slowing down too much. (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 largest amount of data (in units of MB per second) that can be transported over the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR type memory, the result should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the better the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are processed per second. This figure is worked out by multiplying the total amount of texture units by the core 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 processed in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the graphics card could possibly write to its local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate is also dependant on many other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.