I've got a beefy synology nas and a variety of macs and have always had issues with smb shares, despite applying the configuration tweaks even apple recommends on their support site. i get full gigabit-speed as expected when using nfs, though, so i stick with that.
Huh, interesting, I also have a decent synology (ds1621xs+), and feel like I haven't experienced too many issues with it. Time Machine over smb is wonky, but time machine overall is just wonky.
And another one, working with / copying many small files is always pretty bad, but I mostly use it for larger files.
I just tried copying a large video file onto the NAS via smb and get around 700MB/s, which is around what I would expect for the setup (5 * 16TB ironwolf pro in raid5, connected via thunderbolt to an sfp+ adapter). Few other things you could try apart from those articles:
* `defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool TRUE` to not write the DS files to network locations
* Connect via IP address in cmd+K connect window.
* _Turn off_ wifi completely when you connect via ethernet. Otherwise it's very likely the connection will still end up going through the wifi interface.
* Enable jumbo frames on the interface (mtu 9000).
* Check `smbutil statshares -a`. You want SMB 3. If it's a LAN and you don't care about encryption, then `SMB_CURR_ENCRYPT_ALGORITHM` should be `off`.
There are a few, but these links should get you started and hint at future keywords for search. The first link is the one I was thinking of, but there are more. YMMV with link 3 (samba wiki).
