Shared resources lagging - any suggestions?

Basically I have a number of users using a Web-based app. These users here in Europe are switching between the web based app and a mapped drive to save/open/modify documents on a mapped drive (which is located on a server in the US).
There are 20-30 users having this problem.
I have tried decreasing the packet size to 1400 but the problem persists.
I don't have access to the server.
Any suggestions?
There are 20-30 users having this problem.
I have tried decreasing the packet size to 1400 but the problem persists.
I don't have access to the server.
Any suggestions?
Comments
Are all users in the same locations having the problem? (some users deal with slowness better than others by the way)
You may learn something!
ALso when you say you dont have access to the server is that just physically or remotely aswell?