Enabling the 3 GB Feature on 32-Bit Systems

When you run Revit as a 32-bit application on Windows® 7, it is limited to 4 GB of virtual address space. Typically, on a 32-bit system, Microsoft® Windows® reserves 2 GB of the 4 GB virtual address space of any process for the operating system and leaves the remaining 2 GB for the application process (including the space for the code pages, the stack, and all dynamically allocated memory). The 3 GB feature divides the virtual address space differently on 32-bit systems, providing 3 GB for the application and 1 GB for the operating system.

Note: The 3 GB feature is not used for 64-bit versions of Windows.

Before enabling the 3 GB feature, see 3 GB Feature Considerations. Verify that you have sufficient virtual memory allocated for your purposes before enabling the 3 GB feature, as follows.

To verify virtual memory allocation on Windows 7

1. Click Start menuControl Panel.
2. In the Control Panel, double-click System and Security.
3. Click Systems.
4. Click Advanced system settings.
5. In the System Properties dialog, click the Advanced tab.
6. In the Performance field, click Settings.
7. In the Performance Options dialog, click the Advanced tab.
8. In the Virtual Memory field, click Change.
9. In the Virtual Memory dialog, clear the option Automatically manage paging file size for all drives.
10. Select Custom Size.
11. Change the Initial size and Maximum size values to twice your physical memory.

    Physical Memory	Recommended Paging File
    2 GB	4096 MB
    3 GB	6144 MB
    4 GB	8192 MB

    Your system should have at least 3 GB set aside for the paging file size to take full advantage of the available address space. Every concurrently running application is sharing the available paging file size, so setting it to something more than 3 GB (such as 4 GB) is recommended.

12. Click Set.
13. Click OK.

To enable the 3 GB feature on Windows 7

1. Click Start menuAll ProgramsAccessories, then right-click Command Prompt and select Run as administrator.
2. At the command prompt, enter the following:

   bcdedit /set IncreaseUserVa 3072

3. Restart the computer.

To disable the 3 GB feature on Windows 7

1. Click Start menuAll ProgramsAccessories, then right-click Command Prompt and select Run as administrator.
2. At the command prompt, enter the following:

   bcdedit /deletevalue IncreaseUserVa

3. Restart the computer.

See the product support page for more information.