Network Slowdown & Open Directory

We now have approximately 80 computers on Open Directory. We have installed two 48 port Gigabit Switches that run out to the various locations that spans two floors and two buildings. Some of our users have been complaining about the "Spinning Beach Ball of Death" while others do not complain. The most complaints come from G4 eMac users while G5 & Intel users tend not to have the issues.

First, is anyone else here with a similar user count running Open Directory?

Second, are there any easy tip, tricks or tweaks to get the system faster?

Thanks.

iMac Therefore I Am