Hmm. I had forgotten about "sudo purge". It flushes out some cache files as well as RAM.

But I'm not convinced that's useful on recent Mac OS'es. Maybe, but caches generally speed things up, not slow them down. As we really don't know what it decides to purge, it might be things that will just go right back and cost more CPU in doing so.

And on my M1, I don't have need for any speedup now.