If it's the transfer speed, the problem could be the network.
If it's the time it takes to display the dialogs, it could be the database. (Rebuild your indexes.)
check to see if the server(s) are doing a data backup,
Make sure IT didn't add your C: drive to the antivirus autoscan list. That killed us for a while.
We run into this from time to time. The first time was because the server processor was overtaxed due to all the searches being performed on the database side. (We have since split our database and archive servers to two physical machines and really beefed up the database server; dual quad core processors with 12GB ram.) We had slow issues when our IP phones were being updated. We had slow issues when we pushed Windows updates out to all the users. Etc., etc., etc.
I guess what I am getting at is there any number of reasons for slow response times with EPDM, and it is usually something to do with the network or the client machine not pointing to the servers correctly. The fun part is trying to figure out what is different now than before.