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Memory Allocation

If you work with large data sets such as large assemblies, smaller assemblies with complex parts, etc., SolidWorks might need more memory that a 32-bit system allocates to user processes such as SolidWorks.


A 64-bit operating system with sufficient hardware resources is recommended when working with large data sets such as large assemblies, assemblies with complex parts, etc. For system hardware and operating system requirements and recommendations, see SolidWorks System Requirements. With a 64-bit operating system, SolidWorks can address up to 8 TB of memory.


A 32-bit Microsoft Windows NT-based operating system allows a maximum of only 4GB of RAM. By default, 2GB is allocated to the operating system and 2GB is allocated to applications. While not recommended as a long term solution, in a 32-bit Windows XP Professional system, you can adjust the memory allocation. The /3GB switch allows 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. 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 Windows XP Professional:

  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.

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

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

Typical boot.ini file. (Your file might be slightly different.)

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.

  1. Restart your computer.

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


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