Compare any two graphics cards:
GeForce GTX 470 vs Radeon HD 4850 1GB
IntroThe GeForce GTX 470 features a core clock speed of 607 MHz and a GDDR5 memory speed of 837 MHz. It also uses a 320-bit bus, and makes use of a 40 nm design. It is made up of 448 SPUs, 56 TAUs, and 40 ROPs.
Compare those specs to the Radeon HD 4850 1GB, which uses a 55 nm design. AMD has set the core speed at 625 MHz. The GDDR4 RAM runs at a frequency of 993 MHz on this specific card. It features 800(160x5) SPUs along with 40 TAUs and 16 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
Theoretically speaking, the GeForce GTX 470 should be quite a bit faster than the Radeon HD 4850 1GB overall. (explain)
Texel RateThe GeForce GTX 470 should be much (more or less 36%) faster with regards to texture filtering than the Radeon HD 4850 1GB. (explain)
Pixel RateThe GeForce GTX 470 is much (more or less 143%) better at AA than the Radeon HD 4850 1GB, and also should 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.
Memory Bandwidth: Bandwidth is the maximum amount of data (counted in megabytes per second) that can be transported over the external memory interface in one second. It's worked out by multiplying the bus width by the speed of its memory. If it uses DDR RAM, it should be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. 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 number of texture map elements (texels) that can be applied per second. This figure is calculated by multiplying the total texture units of the card by the core speed of the chip. The higher this number, 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 graphics card could possibly record to the local memory per second - measured in millions of pixels per second. The number is calculated by multiplying the amount of Raster Operations Pipelines by the the core clock speed. ROPs (Raster Operations Pipelines - also sometimes called Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel fill rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the ability to get to the max fill rate.