Memory Configuration and /3GB /PAE Switches

  • All:

    We have a new Windows server and are working on configuring the memory. Read a lot about /3GB , /PAE , AWE and got a little bit confused so thought I will post it here and see what do you folks thinks how I am going to configure?

    Our New Windows Environment.

    Windows 2003 Enterprise Edition (32 bit)

    Memory - 16 GB

    SQL 2005 Enterprise Edition (32 bit)

    I would like to give not more than 2 GB for the OS / Kernel (14 GB we want for SQL) and based on that here is what I am planning to configure. Let me know if I am right or wrong?

    On Windows Enable the /3GB /PAE switch

    On SQL Server Enable AWE and set the MAx Server Memory to 14 GB

    Thanks !

  • That is what we did but we capped ours at 12 GB. It showed incredible gains in efficiency.

    Edit: ours was only SQL 2000 that we did this on.

  • ensure you configure the "lock pages in memory" local security policy for the account SQL runs under. Generally its not recommended to use the /3GB switch for machines with 16GB RAM and over. Using the /3GB switch with machines using large amounts of RAM (reportedly 12GB and over) can effect the way the machine addresses the memory

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • So only Enabling /PAE should also help.., right?

  • Milton Gonsalves (7/25/2008)


    So only Enabling /PAE should also help.., right?

    Not from what I have read. PAE just lets windows utilize all the memory. AWE has to be turned on in SQL for SQL to be able to use more.

    Edit: We didn't see the performance increase until we turned on AWE in SQL.

  • Milton Gonsalves (7/25/2008)


    So only Enabling /PAE should also help.., right?

    if your using win 2003 enterprise it should address all the RAM straight off without editing the boot.ini

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Perry Whittle (7/28/2008)


    Milton Gonsalves (7/25/2008)


    So only Enabling /PAE should also help.., right?

    if your using win 2003 enterprise it should address all the RAM straight off without editing the boot.ini

    When installing Win 2003 Enterprise (32-bit), it will automatically recognize the need for the /PAE switch and should add it automatically to the boot.ini. If that switch is not already there, it does need to be added. Win 2003 64-bit does not require the /PAE switch, 32-bit does.

  • jim.powers (7/28/2008)


    If that switch is not already there, it does need to be added.

    on the very rare odd occasion and normally for older processor architecture. 99% of the time the processor architecture will automatically configure the boot.ini at install time with the DEP option /noexecute. This switch implies and automatically switches on /PAE

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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