In System Center Operations Manager, agents may consume 100 percent of CPU resources for the Monitoringhost.exe process.
To resolve this problem, apply hotfix 968967. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
968967 The CPU usage of an application or a service that uses MSXML 6.0 to handle XML requests reaches 100% in Windows Server 2008, Windows Vista, Windows XP Service Pack 3, or other systems that have MSXML 6.0 installed
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.