See these links
to explain the difference between SP1 and the June CU.
- SharePoint 2010 SP1 contains all SharePoint updates published through the April 2011 Cumulative Update in addition to other fixes that were applied specifically to SP1 during its development. SP1 is a baseline, and that baseline is tied to our Service Pack Life Cycle Policy. We recommend applying SP1 to your SharePoint environment because it resets the baseline for your entire SharePoint environment, and prepares your environment for future releases such as the June CU.
- The June Cumulative Update is the first Post-SP1 build released to customers. It contains new fixes to issues raised through various escalation channels and through our support organization. The June CU is based on Service Pack 1, but it adds new updates to some of (not all) the packages that SP1 installs.
The recommended approach is to apply Service Pack 1 and the June CU into an environment together. Because the packages changed by the June CU supersede SP1, the order of installation isn’t critical. If you install the CU before SP1, the packages that the CU updated won’t be overwritten by SP1. Because the June CU is from a later build than SP1, many will be comfortable installing SP1 first, and then applying the CU.
A separate topic of conversation is the order in which you should apply SharePoint Foundation vs. SharePoint Server Updates. Per the guidance from the SharePoint team, when applying SP1 or the CU it is recommended to apply the Foundation packages before applying the server packages.
The recommended order of installation is as follows:
You can then run the Configuration Wizard (PSConfig) one time on all boxes.
Some links which will help in planning and executing your SharePoint 2010 SP1 and SharePoint 2010 June CU deployment:
http://technet.microsoft.com/en-us/sharepoint/ff800847.aspx – Updates for SharePoint Products
http://technet.microsoft.com/en-us/library/ff806326.aspx – SharePoint Foundation Updates
http://technet.microsoft.com/en-us/library/ff806329.aspx – SharePoint Server Updates
http://support.microsoft.com/kb/2510766 – List of all SharePoint Server 2010 SP1 Packages
http://support.microsoft.com/kb/2532120 – Technical Details about the SharePoint 2010 SP1 and Office Server 2010 releases
http://support.microsoft.com/kb/2536599 – Description of the June CU for SharePoint Server 2010
http://technet.microsoft.com/en-us/library/ff806338.aspx – Install a Software Update for SharePoint Server 2010