Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 has a core clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also features a 128-bit bus, and uses a 28 nm design. It is comprised of 384 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.
Compare all of that to the Radeon HD 5850, which makes use of a 40 nm design. AMD has set the core speed at 725 MHz. The GDDR5 memory works at a frequency of 1000 MHz on this specific card. It features 1440(288x5) SPUs along with 72 TAUs and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 5850 should be a lot faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe Radeon HD 5850 is quite a bit (approximately 81%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 5850 is quite a bit (approximately 61%) more effective at FSAA than the GeForce GT 640 DDR3, and also 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: Memory bandwidth is the maximum amount of information (counted in megabytes per second) that can be transferred across the external memory interface in one second. The number is calculated by multiplying the card's bus width by its memory speed. In the case of DDR type memory, the result should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the faster 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 worked out by multiplying the total number of texture units by the core speed of the chip. The higher this number, the better the video 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 maximum number of pixels that the graphics card can possibly record to the local memory per second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the amount of colour ROPs by the clock speed of the card. 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 fill rate is also dependant on lots of other factors, most notably the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.