Windows System Assessment Tool

From Wikipedia, the free encyclopedia
  (Redirected from Windows Experience Index)
Jump to: navigation, search
Developer(s) Microsoft
Operating system
Platform x86, x86-64
Type Computer performance measurement
Website Windows System Assessment Tool at MSDN

The Windows System Assessment Tool (WinSAT) is a module of Microsoft Windows Vista, Windows 7, and Windows 8 that is available in the Control Panel under Performance Information and Tools (except in Windows 8.1). It measures various performance characteristics and capabilities of the hardware it is running on and reports them as a Windows Experience Index (WEI) score. The WEI includes five subscores: processor, memory, 2D graphics, 3D graphics, and disk; the basescore is equal to the lowest of the subscores.[1][2] WinSAT reports WEI scores on a scale from 1.0 to 5.9 for Windows Vista,[3] 7.9 for Windows 7,[4] and 9.9 for Windows 8.[5]

The WEI enables users to match their computer hardware performance with the performance requirements of software. For example, the Aero graphical user interface will not automatically be enabled unless the system has a WEI score of 3 or higher.[6][7]

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 upgrade than adding a faster hard drive (or any other component).[2]

Detailed raw performance information, like actual disk bandwidth, can be obtained by invoking winsat from the command line. This also allows only specific tests to be re-run.[8] Obtaining the WEI score from the command line is done invoking winsat formal, which also updates the value stored in %systemroot%\Performance\WinSAT\DataStore.[9] (The XML files stored there can be easily hacked to report fake performance values.[10]) 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.[11]

The Windows Experience Index score is not displayed in Windows 8.1 because the graphical user interface for WinSAT was removed in this version of Windows, although the command line winsat tool still exists and operates correctly.[12] According to an article in PC Pro, Microsoft removed the WinSAT GUI in order to promote the idea that all kinds of hardware run Windows 8 equally well.[13]


WinSAT in Windows Vista and Windows 7 performs the following tests:

  • Direct3D 9 Aero Assessment
  • Direct3D 9 Batch Assessment
  • Direct3D 9 Alpha Blend Assessment
  • Direct3D 9 Texture Load Assessment
  • Direct3D 9 ALU Assessment
  • Direct3D 10 Batch Assessment
  • Direct3D 10 Alpha Blend Assessment
  • Direct3D 10 Texture Load Assessment
  • Direct3D 10 ALU Assessment
  • Direct3D 10 Geometry Assessment
  • Direct3D 10 Constant Buffer Assessment
  • Windows Media Decoding Performance
  • Windows Media Encoding Performance
  • CPU Performance
  • Memory Performance
  • Disk Performance (includes devices such as Solid-state drives)

While running, the tests show only a progress bar and a "working" background animation. Aero Glass is deactivated on Windows Vista and Windows 7 during testing so the tool can properly assess the graphics card and CPU.

In Windows 8 WinSAT runs under the maintenance scheduler every week. The default schedule is 1am on Sundays. The maintenance scheduler collates various OS tasks into a schedule so the computer is not being randomly interrupted by the individual tasks. The scheduler wakes the computer from sleep, runs all the scheduled tasks and then puts the computer back to sleep. During this weekly task WinSAT runs long enough to detect if there have been any hardware changes. If so the tests are run again. If not WinSAT simply ends as the existing scores must be valid.

WinSAT cannot perform the above tests when a laptop is battery-operated.


  1. ^ "Windows 7 WEI Scores 6.0 through 7.9 Explained". Softpedia. Retrieved June 3, 2011. 
  2. ^ a b "Earning the top Windows Experience Index score". Microsoft. Retrieved June 3, 2011. 
  3. ^ Vista Team Blog : Windows Experience Index: An In-Depth Look
  4. ^ Marco Chiappetta (September 8, 2011). "How to Max Out Your Windows Performance for $1000". PC World. Retrieved May 17, 2014. 
  5. ^ "WinSAT Comprehensive". MSDN. October 20, 2013. Retrieved May 17, 2014. 
  6. ^ "Full screen previews have got disabled. How do I re-enable them?". Microsoft. Retrieved June 3, 2011. 
  7. ^ "What Is the Windows Experience Index". Microsoft. Retrieved June 3, 2011. 
  8. ^ Winsat Command-Line Utility
  9. ^ How can I run the Windows System Assessment Tool (WinSAT) update directly from a command line?
  10. ^ Stupid Geek Tricks: Hacking the Windows Experience Index
  11. ^ "Windows Experience Index: Overview". Microsoft TechNet. Retrieved September 24, 2011. 
  12. ^ Ed Rhee (January 2, 2014). "Find your Windows Experience Index scores in Windows 8.1". CNET. Retrieved May 17, 2014. 
  13. ^ Darien Graham-Smith (September 19, 2013). "Farewell to the Windows Experience Index". Retrieved May 17, 2014. 

External links[edit]