_rick_v_

blastdoor said:

Perhaps it was previously reported that APFS would come to iDevices first, but if so I missed it. 

In any event I think that's actually a great idea. Given that the file system on iDevices is invisible to users and much more tightly controlled than on the Mac, it makes sense to bring it there first. 

I'm very much looking forward to it on the Mac, though. I look forward to a big reduction in beach balls when external drives spin up for time machine backups! 

If you have a Mac with a spinning drive, you probably won't see much improvement.  One of the primary features of APFS is optimized (and therefore faster) performance on SSD drives, by eliminating vast swaths of code that deals with, for example, latency delays due to waiting for the right sector to spin around on the platter.

As far as external drives, APFS isn't going to magically make a drive spin up faster.  That's a function of the hardware itself (i.e. the physical external drive).  The Mac can't do anything with that drive until it's spun up and reports it's online.