Compare any two graphics cards:
GeForce 9800 GT 1GB vs GeForce 9800 GT 512MB
IntroThe GeForce 9800 GT 1GB makes use of a 65/55 nm design. nVidia has clocked the core frequency at 600 MHz. The GDDR3 memory runs at a frequency of 900 MHz on this card. It features 112 SPUs along with 56 Texture Address Units and 16 Rasterization Operator Units.
Compare those specifications to the GeForce 9800 GT 512MB, which has GPU clock speed of 600 MHz, and 512 MB of GDDR3 memory set to run at 900 MHz through a 256-bit bus. It also features 112 Stream Processors, 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 memory bandwidth, so in theory they should perform the same. (explain)
Texel RateBoth cards have exactly the same texel rate, so theoretically they should perform equally good at at anisotropic filtering. (explain)
Pixel RateBoth cards have the exact 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 max amount of information (in units of megabytes per second) that can be moved across the external memory interface in one second. The number is worked out by multiplying the bus width by the speed of its memory. If it uses DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher 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 texture map elements (texels) that are applied in one second. This is calculated by multiplying the total amount of texture units by the core clock 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 the video card can possibly write to its local memory in a second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate is also dependant on lots of other factors, especially the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.