Have an issue and am pretty sure it is problem with the way MYOB works, but I thought I would throw it out there to see if anyone else is having the same issues.

The Original Setup:

3 x Windows XP, peer to peer workgroup.
1 of the XP workstations had MYOB data files located on it along with a local copy of MYOB installed. The other two had local copies of MYOB installed and opened the data file on the first PC.
1 x D-Link Giga switch

The Current Setup:

1 x Windows 2008 DC with MYOB shared folder
2 x Windows 7 Pro - Joined to domain, MYOB installed
1 x Windows XP Pro - Joined to domain, MYOB installed
1 x D-Link Giga Switch (Same as above)

The Issue:

The issue was explained to me by the client that the speed of MYOB has dropped since the install of the new system.

What I found when onsite was that if only one user is logged into MYOB the speed is like how it was under the original setup (no matter what pc is logged in). However as soon as another person logs in the speed drops down, then add a third person and it becomes slower again.

In my mind, the issue is with how MYOB handles multi user network access to its flat file database.

I have seen several forums speaking of the same issue (with no resolution) and they all say running MYOB under Terminal services (E.g. XPUnlimited, MS Terminal Server) solves their issues.  This leads me to beleive that it is not a problem with mulit user access to the MYOB flat database file, but how that flat database file handles multiple user access across a network.

Has anyone else seen this before?

I have done all the basic troubleshooting steps (disabling AV, checked cabling, replaced switch, updating NIC drivers, checked performance of server) to no avail.