The following tip was excerpted from my book Training Guide: Installing and Configuring Windows Server 2012 from Microsoft Press:
Although security filtering is fast, WMI filtering can be slow. Improper use of WMI filtering can therefore have a significant performance impact on how Group Policy is processed and applied. As a result, you should be sure to test the performance of any WMI filter before you deploy it in your production environment. Examples of WMI filters that usually evaluate quickly include filters that query for registry keys or environment variables. WMI filters that might evaluate slowly include filters that query the CIM_DataFile namespace or for installed products using the MSI database.
An alternative to using WMI filtering in many scenarios is to use the Item-Level Targeting feature of Group Policy Preferences, which allows you to change the scope of individual preferences so that they apply only to the specified users or computers. For example, by using Item-Level Targeting, you can allow a preference item to be applied only if the targeted computer has a battery, has a certain amount of free disk space available, has an IP address within a specified range of addresses, and so on. For more information about using Item-Level Targeting, see http://www.wservernews.com/go/1403785178215.
The above tip was previously published in an issue of WServerNews, a weekly newsletter from TechGenix that focuses on the administration, management and security of the Windows Server platform in particular and cloud solutions in general. Subscribe to WServerNews today by going to http://www.wservernews.com/subscribe.htm and join almost 100,000 other IT professionals around the world who read our newsletter!
Mitch Tulloch is a twelve-time recipient of the Microsoft Most Valuable Professional (MVP) award and a widely recognized expert on Windows Server and cloud computing technologies. Mitch is also Senior Editor of WServerNews. For more information about him see http://www.mtit.com.