Security and encryption

[Wando64]

I have recently started to worry about the data safety on one of my Macs (late 2012 quad i7) in case the actual machine gets stolen, however I am reluctant to go full blown FileVault as I am worried it might slow the machine down.

I keep my most sensitive data on a separate folder so that it doesn't get uploaded and synched to my OneDrive.
One possible solution could be to encrypt only that folder and keep it permanently mounted.

Do you think this would provide the same level of security of File Vault? (albeit only for the encrypted folder, of course).
Can you think of any downsides to this approach?

EDIT: one thought, for example: would Time Machine treat the encrypted folder as separate files or as a single .dmg and backup the whole thing everytime something changes?

 

[junkw]

I'd advise to use Filevault first on entire disk, and if you see a notable impact on speed that you can feel, just unencrypt it and go for another solution.

I mean, even if you read somewhere that filevault impact the speed, if you can't feel the difference in use, no worth it to use something more complicated.
If you have a HDD I woudl advise to upgrade to a SSD first