Compare any two graphics cards:
GeForce 8600 GT 1GB DDR2 vs GeForce 8600 GT 512MB DDR2
IntroThe GeForce 8600 GT 1GB DDR2 has clock speeds of 540 MHz on the GPU, and 400 MHz on the 1024 MB of DDR2 memory. It features 32 SPUs along with 16 TAUs and 8 ROPs.
Compare those specifications to the GeForce 8600 GT 512MB DDR2, which comes with a clock speed of 540 MHz and a DDR2 memory speed of 400 MHz. It also uses a 128-bit memory bus, and uses a 80 nm design. It is comprised of 32 SPUs, 16 TAUs, and 8 ROPs.
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have the exact same memory bandwidth, so in theory they should have identical performance. (explain)
Texel RateBoth cards have exactly the same texel rate, so theoretically they should be equally good at at AF. (explain)
Pixel RateBoth cards have exactly the same pixel fill rate, so theoretically they should be equally good at at full screen anti-aliasing, and be capable of handling 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: Bandwidth is the maximum amount of data (measured in MB per second) that can be transported past the external memory interface in one second. It's calculated by multiplying the bus width by the speed of its memory. If it uses DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is calculated by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly record to its local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - sometimes also referred to as 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, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to get to the max fill rate.