I can pull about 700MB/s off my NAS over a 10Gb link. I wouldn’t exactly call it slow.

In a corporate environment SMB3 on MacOS was lagging Windows and Linux big time (at least a few years ago when I tested).

How's the latest to your NAS? Are those single large files or many small files ?

I think SMB is quite chatty -- if you have lots of small files, you can get quite slow.

You can mount webdav — which has been more reliable for us.

That was SMBv1. Not SMB of today.

Still true for extended attributes, which Finder and Spotlight love to query.

...and don't even get me started on locking, if many people write to one file you're on borrowed time