Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 features a clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also features a 128-bit memory bus, and makes use of a 28 nm design. It features 384 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.
Compare those specifications to the Radeon HD 5850, which has core speeds of 725 MHz on the GPU, and 1000 MHz on the 1024 MB of GDDR5 memory. It features 1440(288x5) SPUs along with 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 be 124% faster than the GeForce GT 640 DDR3 overall, because of its higher data rate. (explain)
Texel RateThe Radeon HD 5850 is quite a bit (more or less 81%) more effective at texture filtering than the GeForce GT 640 DDR3. (explain)
Pixel RateIf running with high levels of AA 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 data (in units of megabytes per second) that can be transported across the external memory interface within a second. It is worked out by multiplying the card's interface width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the better the card will be in general. It especially helps with anti-aliasing, HDR and high resolutions.
Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that can be processed per second. This figure is calculated by multiplying the total number of texture units by the core speed of the chip. The higher the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels applied per second.
Pixel Rate: Pixel rate is the maximum amount of pixels the graphics card can 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 ROPs by the clock speed of the card. 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 also depends on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to reach the max fill rate.