It is a long known case that the Finder is appallingly bad when accessing a remote file server.
I agree on the face of it 'merely' listing names of files in a folder should not take as long as the Finder does. However the reality is that the Finder is not merely listing the names of files in a folder.
It gets…
- Names
- Sizes
- Kind
- Creation date, modification date, last accessed date
- Icons
- Tags/Labels
- and probably a lot more besides
In other words vastly more than a simple list of names and therefore not only needs to transfer far more data in total but also has to engage in far more transactions with responses and delays and acknowledgements for each.
So not only is the Finder itself extremely poorly 'optimised' - an oxymoron if ever there was one, but it does a lot of things you are not necessarily aware of and you cannot turn these off.
In the Windows world the equivalent of the Finder is 'Explorer' not to be confused with Internet Explorer. It does not ask for as much information for each file and the impression I get is that is far better optimised as well. Furthermore Windows machines obviously use the SMB protocol whereas it is still the case that most Mac users use AFP. A lot of WAN equipment particularly the category of devices known as WAN accelerators are able to further optimise SMB network traffic but not AFP traffic. (Less likely to be applicable to a remote VPN user, more applicable to site-to-site links.)
If you are currently using AFP I would try SMB. Even if the Finder is just as bad and as I suspect you will not get any WAN accelerator boost, it is going to be the case that Apple themselves have stopped work to improve AFP and that in normal use now with the latest Apple software SMB is faster than AFP.
Depending on what you are trying to do it may also be worth trying WebDav instead.