Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 comes with a clock frequency of 900 MHz and a DDR3 memory speed of 1782 MHz. It also features a 128-bit memory bus, and uses a 28 nm design. It is made up of 384 SPUs, 32 Texture Address Units, and 16 Raster Operation Units.
Compare that to the Radeon HD 5850, which makes use of a 40 nm design. AMD has set the core frequency at 725 MHz. The GDDR5 memory runs at a speed of 1000 MHz on this specific card. 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 much faster than the GeForce GT 640 DDR3 overall. (explain)
Texel RateThe Radeon HD 5850 is a lot (more or less 81%) faster with regards to AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 5850 is a lot (approximately 61%) more effective at full screen anti-aliasing than the GeForce GT 640 DDR3, and also will be capable of handling higher resolutions while still performing well. (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 data (in units of MB per second) that can be transferred across the external memory interface in one second. It's worked out by multiplying the card's interface width by its memory speed. In the case of DDR type memory, it must be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better 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 number of texture map elements (texels) that are applied in one second. This number is calculated by multiplying the total amount of texture units 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 one second.
Pixel Rate: Pixel rate is the maximum amount of pixels that the graphics chip can possibly write to the local memory in one second - measured in millions of pixels per second. The figure is calculated 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 output rate is also dependant on lots of other factors, most notably the memory bandwidth - the lower the bandwidth is, the lower the ability to get to the maximum fill rate.