Exchange 2010, GUI very very slow

Hi all,

we changed from 2007 to 2010 but Exchange Management Console is very very slow

Example: If you "Manage Full Access Permission" an add a User you must wait and wait until all object are loaded. under 2007 you can access a User and click OK. Under 2010 you see the use, you can choice the User but OK Button is grey!!!

We are a little company with 1500 user and GUI are slow.

Chris