Memory Allocation

A 32-bit Microsoft Windows NT-based operating system allows a maximum of 4GB of RAM. By default, 2GB is allocated to the operating system and 2GB is allocated to applications. Microsoft has created a switch (/3GB) to allow you to allocate 3GB of RAM to applications by decreasing the amount allocated to the operating system. The SolidWorks software is written to take advantage of the extra RAM available to applications when the /3GB switch is activated. The ability to increase the amount of RAM available to the SolidWorks application might benefit users with very large assemblies. For more information about the /3GB switch, see the Microsoft design article Memory Support and Windows Operating Systems.

IMPORTANT! Windows XP Service Pack 1 (SP1) has known problems in which Windows might not start or might send a "Stop" error message if you activate the /3GB switch. Contact Microsoft Product Support Services to obtain the fixes. For more information, see the following articles in the Microsoft Knowledge Base at http://support.microsoft.com:

328269 - Windows XP SP1 May Not Start with the /3GB or /USERVA Switch

829364 - "Stop" Error Message When You Start Windows XP by Using the /3GB Switch
 

To activate the /3GB switch in your operating system:

1. Obtain and install any necessary fixes from Microsoft for your operating system.

To see the latest articles and fixes related to the /3GB switch, search the Microsoft Knowledge Base for /3GB.

2. Back up your boot drive (typically drive C).

3. Edit the boot.ini file on your computer, add /3GB as shown, then save the file.

The boot.ini file is a protected system file. You might need to change folder options to view protected system files. For instructions on how to find and edit the boot.ini file, search the Microsoft Knowledge Base for edit boot.ini.

4. Restart your computer.

The operating system now allocates 1GB of RAM to the operating system and 3GB of RAM to applications.

Return SolidWorks Help Index