https://bugzilla.kernel.org/show_bug.cgi?id=206225
--- Comment #10 from Ilia Mirkin (imirkin@alum.mit.edu) --- Sounds like there are things going on that we don't quite understand then... maybe Ben can weigh in.
If the cipher method is disabled (aka CRYPT), it will fall back to M2MF for copy acceleration. In experiments, this is slightly slower but still accelerated.