Compare any two graphics cards:
GeForce 9800 GT 1GB vs GeForce 9800 GT 512MB
IntroThe GeForce 9800 GT 1GB has a core clock speed of 600 MHz and a GDDR3 memory speed of 900 MHz. It also features a 256-bit bus, and uses a 65/55 nm design. It features 112 SPUs, 56 Texture Address Units, and 16 ROPs.
Compare those specifications to the GeForce 9800 GT 512MB, which features core clock speeds of 600 MHz on the GPU, and 900 MHz on the 512 MB of GDDR3 RAM. It features 112 SPUs as well as 56 Texture Address Units and 16 Rasterization Operator Units.
(No game benchmarks for this combination yet.)
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 the same performance. (explain)
Texel RateBoth cards have the exact same texel rate, so theoretically they should be equally good at at anisotropic filtering. (explain)
Pixel RateBoth cards have exactly the same pixel rate, so theoretically they should perform equally good at at anti-aliasing, and be able to handle the same 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 transferred across the external memory interface in a second. It's worked out by multiplying the card's bus width by its memory clock speed. If the card has DDR memory, the result should be multiplied by 2 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 number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total texture units by the core 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 applied in a second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card could possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the amount of Render Output Units by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to reach the maximum fill rate.