need /3GB and /PAE switch

  • Hi, do we need to add switch /3GB in windows 2003 server when we are going to enable AWE to use memory for sql server more 2gb?

    please respond ASAP.

  • No. You should have either /3GB or /PAE enabled. Having them both on on a server with 16+GB memory is asking for problems.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • I am sorry i am not clear with your answere. do you mean if i have both switches enabled i will get a problem? you mean we should enable only one switch?

    we have total 8gb memory in the box and having the problem with sql server and want to allow more memory to sql server. Have enabled AWE but the window guys says we dont need to add /3gb switch in window2003 server and /pae is already bydefault enabled. is that true?

  • Irfan (4/29/2008)


    I am sorry i am not clear with your answere. do you mean if i have both switches enabled i will get a problem? you mean we should enable only one switch?

    Yes and yes.

    /3GB reduces the kernal memory to 1 GB and increases the user memory to 3 GB (instead of the normal 2 and 2).

    /PAE enables the windowing memory functions so that apps can address more than 2 GB of memory.

    As the total amount of memory on the box increases, so the kernal needs more memory to keep track of the memory allocations. If you reduce the kernal's memory to 1 GB on a box with more than 8, you could easily end up with the OS kernal starved for memory.

    /pae is only needed if you have more than 4 GB memory on the server. If you're using /pae (and AWE within SQL) you should not have /3GB enabled.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Thank you very much for your time,now i am leaving for home and see you again if would have a problem.

    Take Care

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