Compare any two graphics cards:
GeForce 9800 GT 1GB vs GeForce 9800 GT 512MB
IntroThe GeForce 9800 GT 1GB uses a 65/55 nm design. nVidia has set the core frequency at 600 MHz. The GDDR3 memory is set to run at a speed of 900 MHz on this particular model. It features 112 SPUs as well as 56 TAUs and 16 Rasterization Operator Units.
Compare those specifications to the GeForce 9800 GT 512MB, which has a clock speed of 600 MHz and a GDDR3 memory frequency of 900 MHz. It also makes use of a 256-bit memory bus, and makes use of a 65/55 nm design. It is made up of 112 SPUs, 56 Texture Address Units, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical BenchmarksBoth cards have the same power consumption.
Both cards have exactly the same bandwidth, so in theory they should perform exactly the same. (explain)
Texel RateBoth cards have the exact same texel fill rate, so theoretically they should perform 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 AA, 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 largest amount of information (in units of MB per second) that can be transported across the external memory interface in a second. The number is worked out by multiplying the interface width by the speed of its memory. If it uses DDR RAM, the result should be multiplied by 2 again. If 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 high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied in one second. This figure is calculated by multiplying the total number 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 in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated by multiplying the number of Raster Operations Pipelines 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 rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.