/3GB

This switch forces x86-based systems to allocate 3 GB of virtual address space to programs and 1 GB to the kernel and to executive components. A program must be designed to take advantage of the additional memory address space. With this switch, user mode programs can access 3 GB of memory instead of the usual 2 GB that Windows allocates to user mode programs. The switch moves the starting point of kernel memory to 3 GB. Some configurations of Microsoft Exchange Server 2003 and Microsoft Windows Server 2003 may require this switch.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

823440 You must use the /3GB switch when you install Exchange Server 2003 on a Windows Server 2003-based system

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

171793 Information on application use of 4GT RAM tuning