Using more than two gigabytes of memory (Windows)

The database server can access shared-memory segments larger than two gigabytes on Windows™.

For Windows version 2003 and earlier, you must enable this feature with an entry in the Windows boot file. Enabling larger shared-memory segments is referred to by Microsoft™ as 4-gigabyte tuning (4GT).

To add the entry, edit the boot.ini file (in the top level, or root directory). You can either add a boot option or use the currently existing boot option. To enable support for more than two gigabytes, add the following text to the end of the boot line:

/3GB

The following example has support for more than two gigabytes enabled:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows NT
Workstation Version 4.00" 
/3GB

The maximum size of the shared-memory segment depends on the operating system, but it is approximately 3 gigabytes for Windows without additional drivers.