Compare any two graphics cards:
GeForce GT 315 vs Radeon HD 3650 512MB
IntroThe GeForce GT 315 has a clock speed of 625 MHz and a DDR3 memory speed of 790 MHz. It also uses a 128-bit memory bus, and uses a 40 nm design. It is made up of 48 SPUs, 16 Texture Address Units, and 8 Raster Operation Units.
Compare all of that to the Radeon HD 3650 512MB, which makes use of a 55 nm design. AMD has set the core speed at 725 MHz. The GDDR3 RAM runs at a frequency of 800 MHz on this specific card. It features 120(24x5) SPUs as well as 8 TAUs and 4 ROPs.
Power Usage and Theoretical Benchmarks
Power Consumption (Max TDP)
In theory, the Radeon HD 3650 512MB is 1% quicker than the GeForce GT 315 in general, because of its higher bandwidth. (explain)
Texel RateThe GeForce GT 315 is quite a bit (about 72%) faster with regards to anisotropic filtering than the Radeon HD 3650 512MB. (explain)
Pixel RateThe GeForce GT 315 is a lot (more or less 72%) more effective at AA than the Radeon HD 3650 512MB, and also will be able to handle higher screen resolutions without losing too much performance. (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 max amount of information (counted in megabytes per second) that can be transported over the external memory interface in a second. The number is worked out by multiplying the card's interface width by its memory speed. In the case of DDR memory, it must be multiplied by 2 once again. If it uses DDR5, multiply by ANOTHER 2x. The higher the memory bandwidth, 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 amount of texture map elements (texels) that are applied per second. This number is worked out by multiplying the total number of texture units by the core speed of the chip. The better the texel rate, the better the 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 number of pixels that the graphics card could possibly write to the local memory in one second - measured in millions of pixels per second. Pixel rate is calculated by multiplying the number of Raster Operations Pipelines by the clock speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for filling the screen with pixels (the image). The actual pixel fill rate also depends on lots of other factors, especially the memory bandwidth of the card - the lower the memory bandwidth is, the lower the potential to reach the max fill rate.