WEI & WinSAT

The Windows System Assessment Tool (WinSAT) is a module of Microsoft Windows Vista and Windows 7 which measures various performance characteristics and capabilities of the hardware it is running on and reports them as a Windows Experience Index (WEI) score, a number between 1.0 and 5.9 for Windows Vista and between 1.0 and 7.9 for Windows 7. The WEI is due to increase its maximum score with future updates.
The WEI includes five subscores: processor, memory, 2D graphics, 3D graphics, and disk; the basescore is equal to the lowest of the subscores.

The WEI allows users to match their computer hardware performance with the performance requirements of software. For example, the Aero graphical user interface recommends a WEI score of 3 or higher for satisfactory use of the "Aero Glass" feature. The WEI can also be used to show which part of a system would be expected to provide the greatest increase in performance when upgraded. For example a computer with the lowest subscore being its memory, would benefit more from a RAM increase than adding a faster hard drive (or any other component).

Microsoft intends that software publishers list WEI scores to specify hardware requirements instead of specific technical parameters (such as "256MB of RAM or more"). Microsoft also intends that hardware manufacturers publish the WEI scores of their computers. However, very few software or hardware vendors have done so to date.

The WEI is also available to applications through an API, so they can configure themselves as a function of hardware performance, taking advantage of its capabilities without becoming unacceptably slow. 

Tests

The current version of WinSAT in Windows Vista (Build 6002) and Windows 7 (Build-7600.16385) performs the following tests:

• Aero Assessment
• Direct3D Alpha Blending Assessment
• Direct3D Texture Load Assessment
• Direct3D ALU Assessment
• Windows Media Playback
• CPU Performance
• Memory Performance
• Disk Performance

While running, the tests show only a progress bar and a "working" background animation. Aero Glass is deactivated during testing so the tool can properly assess the graphics card and CPU.

In addition to tests requested by the user, WinSAT is scheduled to automatically run every week. The default schedule is 1am on Sundays.

It is found under Task Scheduler Library\Windows\Maintenance Also, it is set-up to wait for the computer to be idle for 10 min and give up waiting after an hour. It is also properly configured to not run if the computer is on battery.