Compare any two graphics cards:
GeForce 8600 GT 1GB GDDR3 vs GeForce 8600 GT 512MB DDR2
IntroThe GeForce 8600 GT 1GB GDDR3 comes with a GPU core speed of 540 MHz, and the 1024 MB of GDDR3 memory is set to run at 700 MHz through a 128-bit bus. It also features 32 Stream Processors, 16 Texture Address Units, and 8 ROPs.
Compare all that to the GeForce 8600 GT 512MB DDR2, which comes with core clock speeds of 540 MHz on the GPU, and 400 MHz on the 512 MB of DDR2 RAM. It features 32 SPUs as well as 16 Texture Address Units and 8 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
In theory, the GeForce 8600 GT 1GB GDDR3 should be much faster than the GeForce 8600 GT 512MB DDR2 in general. (explain)
Texel RateBoth cards have exactly the same texel rate, so theoretically they should perform equally good at at AF. (explain)
Pixel RateBoth cards have the exact same pixel fill rate, so in theory they should perform equally good at at anti-aliasing, and be able to handle the same screen resolutions. (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: Memory bandwidth is the maximum amount of information (counted in MB per second) that can be transported past the external memory interface in one second. It is worked out by multiplying the card's bus width by its memory speed. If the card has DDR type RAM, it must be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This is worked out by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied in one second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly write to the local memory in a second - measured in millions of pixels per second. The number is worked out by multiplying the number of Render Output Units by the the core 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 fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.