Compare any two graphics cards:
GeForce 8500 GT vs GeForce GT 640 DDR3
IntroThe GeForce 8500 GT makes use of a 80 nm design. nVidia has clocked the core speed at 450 MHz. The DDR2 memory works at a frequency of 400 MHz on this model. It features 16 SPUs as well as 8 Texture Address Units and 4 Rasterization Operator Units.
Compare those specs to the GeForce GT 640 DDR3, which has GPU clock speed of 900 MHz, and 2048 MB of DDR3 memory running at 1782 MHz through a 128-bit bus. It also is comprised of 384 SPUs, 32 TAUs, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GT 640 DDR3 should be 346% faster than the GeForce 8500 GT in general, due to its higher bandwidth. (explain)
Texel RateThe GeForce GT 640 DDR3 will be a lot (approximately 700%) better at anisotropic filtering than the GeForce 8500 GT. (explain)
Pixel RateThe GeForce GT 640 DDR3 will be quite a bit (more or less 700%) more effective at full screen anti-aliasing than the GeForce 8500 GT, and also should be able to handle higher screen resolutions better. (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 megabytes per second) that can be transferred past the external memory interface in a second. The number is calculated by multiplying the bus width by the speed of its memory. If the card has DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed in one second. This number is worked out by multiplying the total number of texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Render Output Units by the the card's clock speed. 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 also depends on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.