NOTE: Exchange 2010 SP3 allows Exchange 2010 servers to coexist with Exchange 2013 CU1, which is also scheduled to be released in Q1 2013.
Customers can test and validate this update in a representative lab environment prior to rolling out in their production environments as an
important coexistence preparatory step before introducing Exchange Server 2013 CU1.
Support for Windows Server 2012: With SP3, you can install and deploy Exchange Server 2010 on computers that are running Windows Server 2012.
Support for Internet Explorer 10: With SP3, you can use IE10 to connect to Exchange 2010.
Customer Requested Fixes: All fixes contained within update rollups released before SP3 will also be contained within SP3.
Details of our regular Exchange 2010 release rhythm can be found in Exchange 2010 Servicing.
Download Exchange Server 2010 Service Pack 3
Taken from the site of Thanks Team Blog