How to encrypt your entire life in less than an hour
Quincy Larson
23K228

full disk encryption incurs a performance penalty. Even on an SSD you lose about 10–15% IO speed. My source? Tried it myself with a couple spare macs that were identical a few years ago. Reconfirmed a few weeks back when I upgraded the SSD on a laptop, so its not depenent on being the boot volume to be impacted.

10–15% is not a big deal, unless you are already doing stuff that turns your computer into a hair dryer.

I’d also posit encrytion only protects you from someone physically in control of your machine. It doesnt matter once you are logged in, they can simply proxy through you to your disk contents. You were sure that link you clicked was safe right? Nothing seemed to happen…