Compare any two graphics cards:
GeForce 9800 GT 512MB vs GeForce 9800 GTX
IntroThe GeForce 9800 GT 512MB has a GPU core clock speed of 600 MHz, and the 512 MB of GDDR3 RAM is set to run at 900 MHz through a 256-bit bus. It also features 112 Stream Processors, 56 TAUs, and 16 Raster Operation Units.
Compare those specifications to the GeForce 9800 GTX, which has core speeds of 675 MHz on the GPU, and 1100 MHz on the 512 MB of GDDR3 memory. It features 128 SPUs as well as 64 Texture Address Units and 16 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce 9800 GTX should perform a lot faster than the GeForce 9800 GT 512MB in general. (explain)
Texel RateThe GeForce 9800 GTX should be a lot (about 29%) more effective at texture filtering than the GeForce 9800 GT 512MB. (explain)
Pixel RateThe GeForce 9800 GTX will be a small bit (about 13%) better at anti-aliasing than the GeForce 9800 GT 512MB, and 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 maximum amount of information (counted in MB per second) that can be transferred across the external memory interface in one second. It is worked out by multiplying the card's interface width by the speed of its memory. If it uses DDR memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, 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 number of texture map elements (texels) that can be processed per second. This number is calculated by multiplying the total number 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 amount of pixels the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate also depends on many other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.