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 set the core frequency at 450 MHz. The DDR2 RAM is set to run at a speed of 400 MHz on this particular card. It features 16 SPUs as well as 8 Texture Address Units and 4 Rasterization Operator Units.
Compare all of that to the GeForce GT 640 DDR3, which has a core clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also uses a 128-bit bus, and uses a 28 nm design. It features 384 SPUs, 32 TAUs, and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The GeForce GT 640 DDR3 should theoretically perform much faster than the GeForce 8500 GT overall. (explain)
Texel RateThe GeForce GT 640 DDR3 will be much (about 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%) faster with regards to AA than the GeForce 8500 GT, and also will be capable of handling higher resolutions while still performing well. (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 transferred over the external memory interface in a second. The number is worked out by multiplying the interface width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 again. If it uses DDR5, multiply by ANOTHER 2x. The higher the card's memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed in one second. This figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the graphics card will be at 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 that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core 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 also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to reach the max fill rate.