The server only is not enough … need the agent version is higher then 9.5 patch 7 …
Said that, the feature just match data is already available on the database with those already sent from the agent to check it is the same than the one already registered … the following info are used:
select IsVirtualDevice, HardwareInfo, MACAddressList from COMPUTER_REGISTRATIONS
So enable the feature have no specific impact … in general is better restart the server … perform a test on one vm for sure appears appropriate
some references for example here