Compare any two graphics cards:
GeForce 8600 GT 512MB DDR2 vs Radeon HD 5450
IntroThe GeForce 8600 GT 512MB DDR2 has a clock speed of 540 MHz and a DDR2 memory speed of 400 MHz. It also makes use of a 128-bit bus, and uses a 80 nm design. It is made up of 32 SPUs, 16 TAUs, and 8 Raster Operation Units.
Compare that to the Radeon HD 5450, which comes with a clock frequency of 650 MHz and a DDR3 memory frequency of 800 MHz. It also uses a 64-bit bus, and makes use of a 40 nm design. It is comprised of 80(16x5) SPUs, 8 Texture Address Units, and 4 Raster Operation Units.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Both cards have exactly the same memory bandwidth, so theoretically they should perform the same. (explain)
Texel RateThe GeForce 8600 GT 512MB DDR2 will be a lot (about 66%) better at texture filtering than the Radeon HD 5450. (explain)
Pixel RateIf using lots of anti-aliasing is important to you, then the GeForce 8600 GT 512MB DDR2 is a better choice, by a large margin. (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 max amount of data (counted in megabytes per second) that can be transported across the external memory interface in a second. It's calculated by multiplying the bus width by its memory clock speed. If it uses DDR type memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The better the bandwidth is, the faster the card will be in general. It especially helps with AA, HDR and higher screen resolutions.
Texel Rate: Texel rate is the maximum number of texture map elements (texels) that can be applied in one second. This number is calculated by multiplying the total amount of texture units of the card by the core speed of the chip. The better the texel rate, 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 most pixels the graphics card could possibly record to the local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Render Output Units by the the core clock speed. ROPs (Raster Operations Pipelines - also called Render Output Units) are responsible for outputting the pixels (image) to the screen. The actual pixel output rate also depends on quite a few other factors, most notably the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.