Sometimes I bump into an issue with one ore more SCOM/OM12 Agents consuming way too much CPU, even up to 100%. Investigation shows it happens by the MonitoringHost.exe process. This behavior happens on Windows 2003 and Windows Server 2008 servers as well.
Therefore it’s good to know Microsoft has published a KB article about this issue, it’s cause and how to solve it. KB974051 tells you more about it.