A feature in Windows, starting with Vista, that determines the computer's processing speed. The Windows Experience Index (WEI) rates the CPU, RAM, hard disk and display system as individual "subscores" from 1 to 5.9, and the lowest subscore is the "base score." In order to run the Aero interface, a base score of 3 is required, while base scores of 4 and 5 are recommended for gaming and computation-intensive applications.
The WEI Base Score
To view the WEI, select the System control panel in Windows. In this example, the processor subscore is the lowest and thus becomes the base score.