When encrypting drive on Surface Studio using Bitlocker you may encounter slow performance in Windows while the drive is being encrypted
Note: To check status of the encryption run the following command at elevated cmd promptmanage-bde -status <osdriveletter>
In order to encrypt the drive, bitlocker must disable the Rapid Hybrid Drive cache in order to encrypt which adds additional time.
Note: The Rapid Hybrid Drive cache is re-enabled once bitlocker encryption is complete
This behavior is by design.