AWE enable and SQL Server 2005 x64 bits

Hello,

I am setting up a new server with Windows Server 2003 x64 bits and SQL Server 2005 x64 bits. Under 32 bits of Windows we normally use /3GB and enable AWE under SQL Server (both SQL 2000 and SQL 2005) and allocate 6 GB of fixed memory to SQL Server.

Does any one know whether I should do the same thing under the x64 bits platform. I read some articles on the web that it is no longer required to use AWE under SQL 2005 x64 bits?

Please advise.

Thanks.

You don't need to enable AWE via sp_configure if you are running the 64bit version on x64, as 64bit SQL doesn't need to use the AWE api to address the larger memory space.

It is recommended to grant the SQL service account the OS privilege "Lock pages in memory". By doing this you are preventing the OS from swapping SQL's memory pages to disk and allowing SQL itself to reduce it's working set when the OS requires it to do so. This should give you a performance benefit under tight memory situations. One of the odd results of using "lock pages in memory" is that we will use the AWE api to map the virtual address space into and out of physical memory (in fact the "lock pages in memory" privilege is a requirement for using AWE with 32bit). As a result the "AWE allocated" value from dbcc memorystatus will show a value, indicating that AWE is enabled even though it is disabled in sp_configure.

In summary, the 64bit version of SQL Server can address all the memory on the server without having to use AWE. A perf benefit may be observed when "lock pages in memory" is enabled and this results in the use of AWE internally, irrespective of the sp_configure setting.

thx, Simon.

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Hi Simon

Thanks you for your advice. Are you suggesting that we should turn on "local pages in memory" under x64 bits platform as well even though SQL can address all the memory on the server?

One more question, do you know if I need /PAE under x64 bits of Windows?

Thanks.

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I just found an article under MS and according to this article from MS, PAE is not available in Windows x64...

Thanks..

|||Do you still need the /3GB switch in a 2005 x64 install if you have 16GB of memory?|||No