Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 uses a 28 nm design. nVidia has set the core frequency at 900 MHz. The DDR3 memory is set to run at a speed of 1782 MHz on this particular model. It features 384 SPUs as well as 32 TAUs and 16 ROPs.
Compare those specifications to the Radeon HD 5850, which has core clock speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 RAM. It features 1440(288x5) SPUs as well as 72 Texture Address Units and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
The Radeon HD 5850 should in theory be a lot faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe Radeon HD 5850 will be a lot (approximately 81%) more effective at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateIf using a high resolution is important to you, then the Radeon HD 5850 is a better choice, and very much so. (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 (measured in megabytes per second) that can be moved past the external memory interface within a second. It is calculated by multiplying the bus width by its memory clock speed. If the card has DDR type RAM, the result should be multiplied by 2 once 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, High Dynamic Range and higher screen resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are processed in one second. This is calculated by multiplying the total texture units by the core speed of the chip. The better this number, the better the video card will be at handling texture filtering (anisotropic filtering - AF). It is measured in millions of texels processed in one second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly record to its local memory in a second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Render Output Units by the clock speed of the card. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the ability to reach the maximum fill rate.