The Microsoft Exchange Replication service consumes excessive CPU resources on Client Access servers in an Exchange Server 2010 environment. This issue occurs even though you do not perform mailbox move operations.
This issue occurs because the Exchange Replication service checks the mailbox databases status too frequently. This causes the service to consume unnecessary CPU resources.
To resolve this issue, install the following update rollup:
2746164 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.