Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 comes with a clock speed of 900 MHz and a DDR3 memory speed of 1782 MHz. It also uses a 128-bit memory bus, and makes use of a 28 nm design. It is comprised of 384 SPUs, 32 TAUs, and 16 ROPs.
Compare all that to the Radeon HD 5850, which comes with a core clock speed of 725 MHz and a GDDR5 memory frequency of 1000 MHz. It also makes use of a 256-bit bus, and makes use of a 40 nm design. It features 1440(288x5) SPUs, 72 Texture Address Units, and 32 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Performance-wise, the Radeon HD 5850 should in theory be a lot better than the GeForce GT 640 DDR3 in general. (explain)
Texel RateThe Radeon HD 5850 is a lot (approximately 81%) more effective at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 5850 will be quite a bit (approximately 61%) more effective at AA than the GeForce GT 640 DDR3, and also will be able to handle higher resolutions more effectively. (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 maximum amount of information (measured in MB per second) that can be transferred across the external memory interface within a second. The number is worked out by multiplying the card's bus width by its memory clock speed. If it uses DDR memory, it should be multiplied by 2 once again. If DDR5, multiply by 4 instead. The better the memory bandwidth, the better the card will be in general. It especially helps with AA, 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 figure is worked out by multiplying the total amount of texture units by the core speed of the chip. The higher the texel rate, the better the card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in one second.
Pixel Rate: Pixel rate is the maximum number of pixels the video card can possibly record to the local memory per second - measured in millions of pixels per second. The figure is worked out by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - sometimes also referred to as Render Output Units) are responsible for drawing the pixels (image) on the screen. 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 maximum fill rate.