I have 4GB RAM installed. PAE is off. How do I tell the Windows 7 32-bit kernel to allocate 3GB virtual paging area to user mode and only 1GB to kernel space?


Start a command prompt with Administrative privileges (write cmd in the Start search and right-click cmd.exe and select Run as Administrator). Write the command bcdedit /set IncreaseUserVA 3072 This increases the user address space to 3GB and shrinks the kernel address space to 1GB.

Do take care: If you have a badly coded driver this change can cause it to crash.


On Windows, you can add the /3GB flag to your boot.ini file to turn on OS level support. However, this will only allow applications that also have the appropriate flag (IMAGE_FILE_LARGE_ADDRESS_AWARE) turned on in their process header (see here for more details).

  • This won't work on Windows Vista and higher. They don't have boot.ini. But that link does explain how it works on Windows Vista so thanks. – unixman83 May 8 '11 at 23:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.