I've been having trouble using FDE on Ubuntu-MATE on my Mid-2015 15" Macbook Pro. When I follow the instructions to install the OS using FDE, the installation goes really slow. When it's finally up and running, updating/upgrading packages goes really slow. Without the encryption it snaps like a whip. Is my computer simply too old to use FDE? I think I used FileVault FDE on this computer when I was running macOS and it worked just fine. Having said that, I understand FileVault uses AES-128, while Ubuntu with FDE uses AES-256. What is causing the slow down? Is there any way to run FDE with a lesser grade encryption to speed it up?
Thanks,
Jimmy