Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 makes use of a 28 nm design. nVidia has set the core frequency at 900 MHz. The DDR3 RAM is set to run at a frequency of 1782 MHz on this particular model. It features 384 SPUs along with 32 TAUs and 16 Rasterization Operator Units.
Compare those specs to the Radeon HD 5850, which has GPU core speed of 725 MHz, and 1024 MB of GDDR5 memory running at 1000 MHz through a 256-bit bus. It also is comprised of 1440(288x5) SPUs, 72 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 5850 is 124% faster than the GeForce GT 640 DDR3 in general, because of its higher data rate. (explain)
Texel RateThe Radeon HD 5850 should be a lot (about 81%) faster with regards to texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with a high resolution is important to you, then the Radeon HD 5850 is superior to the GeForce GT 640 DDR3, by a large margin. (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 largest amount of data (measured in MB per second) that can be transported over the external memory interface within a second. The number is calculated by multiplying the card's interface width by the speed of its memory. In the case of DDR RAM, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the bandwidth is, 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 number of texture map elements (texels) that can be processed per second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The higher this number, the better the 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 that the graphics chip 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 Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate is also dependant on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.