Microsoft KB Archive/94048

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 * Microsoft Windows NT operating system version 3.1

SUMMARY
The About Program Manager dialog box in Windows NT shows the total physical memory installed in the system, but not the free memory or the percentage of free system resources, which are both displayed by Windows 3.0 and 3.1. This is because Windows NT uses resources differently than do Windows 3.0 and 3.1.

MORE INFORMATION
Because Windows NT allocates all physical memory for itself, showing free physical memory would be misleading. Similarly, showing free virtual memory would be misleading because every running application always has close to 2 gigabytes (2048 MB) of memory free. When an application starts, Windows NT allots it 2 gigabytes (GB) of virtual memory. Windows NT then uses a method of memory allocation called &quot;paging&quot; to redirect physical memory into each application's virtual memory. Windows NT often allocates all physical memory because it makes the process of memory paging more efficient.

To see how Windows NT is using memory, use Performance Monitor (in the Administrative Tools group). Keep in mind that having very little free physical memory is not an indication of a problem. Under Windows 3.0 or 3.1, when you are about to start a new application, you may check free memory and system resources before doing so. However, due to the new memory-management schemes for Windows NT, there is almost no need to be concerned about free memory before starting another application. If Windows NT needs more physical memory, it can quickly redirect memory pages so that every application gets the resources and performance it needs.
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Last reviewed: May 6, 1997

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