Compare any two graphics cards:
GeForce 8500 GT vs GeForce GT 640 DDR3
IntroThe GeForce 8500 GT comes with a core clock frequency of 450 MHz and a DDR2 memory speed of 400 MHz. It also features a 128-bit bus, and uses a 80 nm design. It features 16 SPUs, 8 Texture Address Units, and 4 Raster Operation Units.
Compare all that to the GeForce GT 640 DDR3, which has GPU clock speed of 900 MHz, and 2048 MB of DDR3 RAM running at 1782 MHz through a 128-bit bus. It also is comprised of 384 SPUs, 32 Texture Address Units, and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the GeForce GT 640 DDR3 should be quite a bit faster than the GeForce 8500 GT in general. (explain)
Texel RateThe GeForce GT 640 DDR3 will be quite a bit (about 700%) more effective at texture filtering than the GeForce 8500 GT. (explain)
Pixel RateThe GeForce GT 640 DDR3 is quite a bit (more or less 700%) more effective at FSAA than the GeForce 8500 GT, and will be capable of handling higher resolutions without losing too much performance. (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 maximum amount of information (counted in MB per second) that can be transported past the external memory interface in a second. The number is 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 4 instead. The better the 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 are processed per second. This is worked out by multiplying the total texture units of the card by the core clock speed of the chip. The higher this number, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the card's clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the maximum fill rate.