DPA does not collect numerous resource statistics for early releases of SQL Server. This is due to a memory leak in SQL Server caused by SQL Server stored procedures (sp_OAMethod and sp_OAGetProperty) that are called to collect these resources. WMI metric queries can become unresponsive, leave orphaned connections and may require restarting the monitored instance to resolve.
See the following Microsoft articles for more information on the memory leak:
SQL Server versions that do not exhibit the memory leak (DPA collects all resource statistics for these versions):
If your SQL Server instance is at or above these versions, resource statistics may not be collected for other reasons. See this article.