Unable to increase heap size more than 1280


  • Hi All,

    One of my customer is trying to increase the heap settings to 2GB on his Windows machine
    He is using Windows 2000 Advanced Server, and he is able to increase the heap up to 1280m only

    Is it product limitation?

    Wednesday, June 10, 2009 1:55 PM


All replies

  • Hi,

    First of all, you didn't get the correct forum. 

    According to the description, it is not clear enough on the exact heap that you are referring to. Is it Desktop Heap or Java VM heap size or something else?


    For Desktop Heap, the following links are helpful. Generally speaking, the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\SessionViewSize registry value can be used to adjust desktop heap size. SystemViewSize is the desktop heap for drivers. SessionImageSize is the address space where the Win32k.sys file and the Windows NT 4 print drivers are loaded. The theoretical maximum aggregate of these values cannot be greater than 512 MB. In practice, the aggregate is around 450 MB for most configurations.


    Desktop Heap Overview


    Desktop Heap, part 2




    For Java VM heap size, you could refer to the following link and you should contact Sun for more information:


    Tuning WebLogic JRockit JVM



    Best regards,

    Vincent Hu

    Thursday, June 11, 2009 10:38 AM
  • Hi Vincent,

    Thanks for your reply.

    My customer is trying to increase Java heap.

    I am aware of above link, here he is using Sun Java not JRockit.

    He wants to increase the Java heap to 2GB but not able to increase more than 1280m

    Could you let me know on which forum i need to go?

    Thursday, June 11, 2009 12:57 PM
  • Hi,


    I recommend that you contact Sun for more details.



    Best regards,

    Vincent Hu


    Friday, June 12, 2009 2:34 AM