In Microsoft SQL Server 2008 R2, the configuration option, awe enabled, is deprecated. In the next version, Microsoft SQL Server 2012, this configuration option and the feature that uses this configuration option are removed from the product.
Therefore, when you upgrade from SQL Server 2008 R2 to the next version of SQL Server, you cannot use more memory than what the virtual address space limits in 32-bit instances of SQL Server. If you must have more memory for this instance of SQL Server, then you have to migrate to a 64-bit instance of SQL Server.
After you upgrade to SQL Server 2012, the maximum amount of memory that can be used by the 32-bit instance of SQL Server is determined as follows.
SQL Server and operating system settings
Maximum amount of memory used by SQL Server
32-bit SQL Server on 32-bit OS
32-bit SQL Server on 32-bit OS with /3G boot option
32-bit SQL Server on 64-bit OS
Carefully review the memory requirements of the existing instance of SQL Server before you upgrade to SQL Server 2012.
The following table provides more information about the products or tools that automatically check for this condition on your instance of SQL Server and on the versions of the SQL Server product against which the rule is evaluated.
Product versions against which the rule is evaluated
System Center Advisor
SQL Server feature awe enabled is deprecated
System Center Advisor determines whether this SQL Server is a 32-bit instance and the configuration awe enabled is set to 1. Review the details that are provided in the “Information Collected” section of the advisor alert, and plan appropriately when you upgrade to the next version of SQL Server.
SQL Server 2008 R2
SQL Server setup Upgrade Rules
Is AWE Enabled Check for x86 installations
The SQL Server 2012 setup program checks if the awe enabled configuration is set to 1 during an upgrade attempt from previous versions of SQL Server. If the configuration is set to 1 on a 32-bit instance of SQL Server, then the SQL Server 2012 setup program blocks the upgrade. You have to first configure the awe enabled option to 0 before attempting upgrade. This upgrade rule is provides appropriate warning to administrators that the total memory that can used by SQL Server instance after upgrade might be less and hence result in performance issues for the applications using the SQL Server instance.