Exchange Powershell Multiple Mailbox Moves

Move-Mailbox has a switch you can set to throttle the number of threads.

• MaxThreads (http://technet.microsoft.com/en-us/library/aa997599.aspx )

You also have to make sure not to run the Move-Mailbox command in a foreach loop that provides one mailbox at a time or else it will only move one at a time...