I bought an external SSD with a USB 3.1 gen 2 enclosure. I'm on macOS 10.13.6 with a MBP (late 2013).
Using APFS I get write speeds of around 390–405 MB/s. So far, so good. However formatting the drive to APFS (encrypted) results in way slower write speeds of around 250–260 MB/s.
Is such a performance loss of nearly 40% normal for an encrypted drive, or am I doing something wrong?
I used a 10GB test file and
cp to measure the performance. Copying through Finder results in similar performance.