Compare any two graphics cards:
GeForce GTX 550 Ti vs Radeon HD 4850 512MB
IntroThe GeForce GTX 550 Ti makes use of a 40 nm design. nVidia has set the core frequency at 900 MHz. The GDDR5 RAM runs at a speed of 1026 MHz on this specific card. It features 192 SPUs as well as 32 Texture Address Units and 24 ROPs.
Compare all that to the Radeon HD 4850 512MB, which comes with GPU core speed of 625 MHz, and 512 MB of GDDR3 memory set to run at 993 MHz through a 256-bit bus. It also features 800(160x5) SPUs, 40 Texture Address Units, and 16 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 550 Ti should be 55% faster than the Radeon HD 4850 512MB overall, because of its higher data rate. (explain)
Texel RateThe GeForce GTX 550 Ti is a bit (approximately 15%) faster with regards to anisotropic filtering than the Radeon HD 4850 512MB. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce GTX 550 Ti 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.
Memory Bandwidth: Memory bandwidth is the maximum amount of information (in units of MB per second) that can be moved over the external memory interface in one second. It is calculated by multiplying the card's interface width by the speed of its memory. If the card has DDR type memory, the result should 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 AA, HDR and high resolutions.
Texel Rate: Texel rate is the maximum texture map elements (texels) that are applied per second. This is calculated by multiplying the total number of texture units of the card by the core clock speed of the chip. The better this number, the better the graphics card will be at 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 card could 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 ROPs by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, most notably the memory bandwidth - the lower the memory bandwidth is, the lower the potential to get to the maximum fill rate.