Compare any two graphics cards:
GeForce 8500 GT vs GeForce GT 640 DDR3
IntroThe GeForce 8500 GT comes with a core clock speed of 450 MHz and a DDR2 memory frequency of 400 MHz. It also features a 128-bit memory bus, and makes use of a 80 nm design. It features 16 SPUs, 8 TAUs, and 4 ROPs.
Compare those specifications to the GeForce GT 640 DDR3, which has a clock frequency of 900 MHz and a DDR3 memory frequency of 1782 MHz. It also features a 128-bit bus, and makes use of a 28 nm design. It features 384 SPUs, 32 TAUs, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GT 640 DDR3 should be quite a bit faster than the GeForce 8500 GT overall. (explain)
Texel RateThe GeForce GT 640 DDR3 is quite a bit (approximately 700%) more effective at AF than the GeForce 8500 GT. (explain)
Pixel RateThe GeForce GT 640 DDR3 should be a lot (about 700%) better at anti-aliasing than the GeForce 8500 GT, and will be capable of handling higher screen resolutions more effectively. (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 data (counted in MB per second) that can be moved over the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 again. If DDR5, multiply by 4 instead. The higher the card's memory bandwidth, the faster the card will be in general. It especially helps with AA, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are applied per second. This is worked out by multiplying the total texture units by the core clock speed of the chip. The higher this number, the better the card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in a second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics card could possibly write to its local memory in a 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 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 also depends on lots of other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.