Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 features a GPU clock speed of 900 MHz, and the 2048 MB of DDR3 memory is set to run at 1782 MHz through a 128-bit bus. It also is comprised of 384 Stream Processors, 32 Texture Address Units, and 16 ROPs.
Compare those specifications to the Radeon HD 5850, which comes with a core clock frequency of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also uses a 256-bit memory bus, and uses a 40 nm design. It is made up of 1440(288x5) SPUs, 72 TAUs, and 32 ROPs.
(No game benchmarks for this combination yet.)
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 5850 should perform a lot faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe Radeon HD 5850 should be quite a bit (about 81%) more effective at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 5850 will be much (approximately 61%) more effective at anti-aliasing than the GeForce GT 640 DDR3, and will be able to handle higher screen 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 largest amount of information (in units of megabytes per second) that can be transferred across the external memory interface in a second. It is worked out by multiplying the card's bus width by its memory speed. If it uses DDR memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, the faster the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that are applied per second. This is worked out by multiplying the total amount of texture units of the card by the core speed of the chip. The higher 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 a second.
Pixel Rate: Pixel rate is the maximum number of pixels that the graphics chip could possibly write to the local memory per second - measured in millions of pixels per second. The number is worked out by multiplying the amount of colour ROPs by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel 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.