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Tested: Windows 11 Pro's On-By-Default Encryption Slows SSDs Up to 45%
(www.tomshardware.com)
This is a most excellent place for technology news and articles.
Just checked an 11 Home computer that has Device Encryption turned on:
Get-BitLockerVolume reports that it is on for the main drive with RecoveryPassword and Tpm protectors.
It's definitely just a rebranded, less featured BitLocker.