Compare any two graphics cards:
GeForce 8500 GT vs GeForce GT 640 DDR3
IntroThe GeForce 8500 GT comes with core clock speeds of 450 MHz on the GPU, and 400 MHz on the 512 MB of DDR2 RAM. It features 16 SPUs as well as 8 TAUs and 4 ROPs.
Compare those specs to the GeForce GT 640 DDR3, which makes use of a 28 nm design. nVidia has set the core speed at 900 MHz. The DDR3 memory runs at a speed of 1782 MHz on this model. It features 384 SPUs as well as 32 Texture Address Units and 16 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the GeForce GT 640 DDR3 should theoretically be much superior to the GeForce 8500 GT in general. (explain)
Texel RateThe GeForce GT 640 DDR3 should be much (approximately 700%) better at AF than the GeForce 8500 GT. (explain)
Pixel RateThe GeForce GT 640 DDR3 will be a lot (approximately 700%) faster with regards to FSAA than the GeForce 8500 GT, and also capable of handling higher 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 max amount of data (in units of megabytes per second) that can be transferred past the external memory interface within a second. It's calculated by multiplying the card's bus width by its memory speed. If the card has DDR memory, the result should be multiplied by 2 again. If DDR5, multiply by ANOTHER 2x. The higher the bandwidth is, the faster the card will be in general. It especially helps with AA, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be processed in one second. This is worked out by multiplying the total amount of texture units by the core clock speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed per second.
Pixel Rate: Pixel rate is the most pixels the graphics card could possibly write to its local memory in one second - measured in millions of pixels per second. The figure is worked out by multiplying the number of colour ROPs by the the core 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 is also dependant on many other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the ability to reach the max fill rate.