Compare any two graphics cards:
GeForce GT 640 DDR3 vs Radeon HD 5850
IntroThe GeForce GT 640 DDR3 comes with core clock speeds of 900 MHz on the GPU, and 1782 MHz on the 2048 MB of DDR3 RAM. It features 384 SPUs along with 32 Texture Address Units and 16 Rasterization Operator Units.
Compare those specs to the Radeon HD 5850, which uses a 40 nm design. AMD has set the core frequency at 725 MHz. The GDDR5 RAM is set to run at a speed of 1000 MHz on this specific model. It features 1440(288x5) SPUs as well as 72 TAUs and 32 Rasterization Operator Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the Radeon HD 5850 will be 124% quicker than the GeForce GT 640 DDR3 overall, due to its higher bandwidth. (explain)
Texel RateThe Radeon HD 5850 will be quite a bit (approximately 81%) more effective at AF than the GeForce GT 640 DDR3. (explain)
Pixel RateThe Radeon HD 5850 is quite a bit (approximately 61%) faster with regards to full screen anti-aliasing than the GeForce GT 640 DDR3, and should be capable of handling higher screen resolutions without slowing down too much. (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 largest amount of data (measured in MB per second) that can be transported over the external memory interface in one second. The number is worked out by multiplying the interface width by its memory speed. If the card has DDR memory, it should be multiplied by 2 again. If 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 number of texture map elements (texels) that are processed in one second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The better the texel rate, the better the graphics card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels per second.
Pixel Rate: Pixel rate is the most pixels the video card can possibly record to its 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 card's clock speed. 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 fill rate is also dependant on many other factors, especially the memory bandwidth - the lower the bandwidth is, the lower the potential to get to the max fill rate.