XADM: Enabling 4GT Switch When Using Windows NT/Enterprise

• Microsoft Exchange Server, version 5.5
• Microsoft Windows NT Server, Enterprise Edition version 4.0

SUMMARY

The information store (Store.exe) and the directory service (Dsamain.exe) have been compiled to make use of up to 3 GB of addressable memory per process when the 4 GB RAM Tuning (4GT) switch is enabled in Microsoft Windows NT Server Enterprise Edition (Windows NT Server/E).

Four GB RAM Tuning (4GT) reallocates RAM within the 4-GB address space of Windows NT Server from the operating system to memory-intensive applications. Using 4GT, a memory-intensive application can use up to 3 GB of RAM, a 50 percent increase over the base Windows NT Server product, so that more data is cached and performance is increased.

This feature benefits applications such as Microsoft Exchange Server that run on powerful computers with more than 2 GB of physical RAM and that can take advantage of a larger address space.

Windows NT Server/E supports 4GT on Intel architecture servers only.

MORE INFORMATION

After you have installed Windows NT Server/E, you must modify the Boot.ini file to enable 4GT. To enable 4GT, add the /3GB parameter to the startup line.

NOTE: This change is only effective if you are using Windows NT Server/E. On standard Windows NT, this flag relocates the kernel, but applications will be unable to access more than 2 GB.

For example:

 [boot loader]
 timeout=30
 default=multi(0)disk(0)rdisk(0)partition(2)\WINNT
 [operating systems]
 multi(0)disk(0)rdisk(0)partition(2)\WINNT="Windows NT Server Version 4.00"
 /3GB
 multi(0)disk(0)rdisk(0)partition(2)\WINNT="Windows NT Server Version 4.00
 [VGA mode]" /basevideo /sos 

Additional query words: scalability

Keywords : XADM
Version : WINDOWS:5.5; WINNT:4.0
Platform : winnt
Issue type : kbhowto