On Linux there is a 3GB/1GB kernel option. How do I do this in Windows 7 32-bit?

Question

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?

Answer 1

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.

Answer 2

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).