FIX: The DBCC CHECKDB statement takes longer to run on an x64-based computer than the statement takes to run on a 32-bit computer when you run the statement against a database in SQL Server 2005

Consider the following scenario. You have an instance of Microsoft SQL Server 2005 that is installed on an x64-based computer. You run the DBCC CHECKDB statement against a database. In this scenario, the statement takes longer to run than it takes to run on a 32-bit computer.

Note This issue also occurs when you run the DBCC CHECKTABLE statement and the DBCC CHECKFILEGROUP statement.

This issue occurs because of the data purity checks that are introduced in SQL Server 2005.

The fix for this issue was first released in Cumulative Update 5. For more information about how to obtain this cumulative update package for SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2005 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:Microsoft SQL Server 2005 hotfixes are created for specific SQL Server service packs. You must apply a SQL Server 2005 Service Pack 2 hotfix to an installation of SQL Server 2005 Service Pack 2. By default, any hotfix that is provided in a SQL Server service pack is included in the next SQL Server service pack.

To work around this issue, follow these steps:

1. Back up the database from the x64-based computer.
2. Restore the database on a 32-bit computer.
3. Run the check statement against the database on the 32-bit computer.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

After you apply this hotfix, you can turn off the data purity checks when you run check statements. You can do this by enabling trace flag 2566. To enable the trace flag, run the following statement.
For more information about what files are changed, and for information about any prerequisites to apply the cumulative update package that contains the hotfix that is described in this Microsoft Knowledge Base article, click the following article number to view the article in the Microsoft Knowledge Base:

For more information about the list of builds that are available after SQL Server Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the Incremental Servicing Model for SQL Server, click the following article number to view the article in the Microsoft Knowledge Base:For more information about how to obtain SQL Server 2005 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the new features and the improvements in SQL Server 2005 Service Pack 2, visit the following Microsoft Web site: For more information about the naming schema for SQL Server updates, click the following article number to view the article in the Microsoft Knowledge Base:For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: