How to find the Windows Experience Index in Windows 8.1/8/10 on my PC (computer rating, performance)?

To vote your PC in Windows 8 or view your computer Experience Index in Windows 8

control.exe /name Microsoft.PerformanceInformationAndTools ( . see Image-1 Arrow-1) and confirm that with [ENTER], or press the [OK] button.

(Image-1) View or rating your computer Experience Index in Windows 8

Info (c) Microsoft:

The Windows Experience Index is a measurement that tells you how well your PC works with Windows and uses a base score to rate the experience you can expect. A higher base score usually means that your PC will be faster and more responsive than a PC with a lower base score.

(Image-2) View Windows 8 computer rating or performance (Experience) index

Info (c) Microsoft:

Each piece of hardware in your PC gets its own score called a subscore. The total base score for your PC is determined by the lowest individual subscore, rather than an average of them all. You can view the subscores to see how the hardware you care most about is performing, which can help your decide whether to upgrade some parts of your PC.