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sql server 2000 sp4 windows 2003 ent pae /3g

  • January 30, 2008 at 9:02 am

    #378223

    After reading too many articles on /PAE and /3G switch I am a bit confused and would need a bit of clarification here.

    8G of Memory sql server 2000 sp4 windows 2000 enterprise edition

    This is the question .I have PAE set .That should make the OS address more memory.Can sql server take advantage of this memory ?

    Would it utilize all the available memory if /3G is not set ?

    Thanks for your time

    MTN

  • May 16, 2008 at 12:54 pm

    #816682

    Just use /PAW switch in boot.ini - Please do not add /3GB

    Recently we had same issue SQL 2000 SP4 on WINDOWS 2003 Advanced server.

    first we tried /3GB / PAW in boot.ini - then we didn't see any improvement.

    After reading so many article we remove /3GB and left with /PAW in boot.ini

    Now everything looks good.

    thanks

    Rajesh

  • May 16, 2008 at 1:29 pm

    #816705

    The 3G switch tells the OS to use less memory for itself. Without this switch set, Windows allocates 2GB out of the first 4GB of memory to OS level operations leaving you with only 2GB of physical memory available for the SQL Service and any other non-OS operations.

    With the PAE switch set and an AWE enabled application, addional memory can be accessed through the AWE extensions. This means the AWE switch will let the SQL Server engine use more memory. Keep in mind that AS2000, and RS2000 are not AWE aware, so they will use portions of the physical memory and then virtual memory.

    Now, the 3G switch is important in that it gives you an additinal 1GB of physical memory. That is important for two reasons. First, AWE memory can only be access by going through a memory map. This memory mapping takes time making AWE memory less-efficient. In addition to this, SQL2000 does not use AWE memory for all types of memory operations. I cannot remember the list, but there are memory operations SQL2000 will not use AWE memory for and it will have to go to virtual memory if physical memory is unavailable.

    What does all of this mean for you? Well, you should do some testing on your system. They all seem to act differently. If you are able to test them both, I would recommend trying with and without and see what your performance difference is.

    Then, I would switch to 64 bit as soon as possible.

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