Q264450: Reduced Working Set Size After Installing Windows NT SP6a
Article: Q264450
Product(s): Microsoft Windows NT
Version(s): 4.0,4.0 SP6,4.0 SP6a
Operating System(s):
Keyword(s): kbenv kbtool kbWinNT400PreSP7Fix
Last Modified: 11-JUN-2002
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The information in this article applies to:
- Microsoft Windows NT Server versions 4.0 SP6, 4.0 SP6a
- Microsoft Windows NT Workstation versions 4.0, 4.0 SP6a
- Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP6a
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IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
Q256986 Description of the Microsoft Windows Registry
SYMPTOMS
========
The upper limit of a program's minimum working set can be significantly less on
a Windows NT 4.0 Service Pack 6a-based computer than what it may be when you are
running Windows NT 4.0 Service Pack 5 or earlier.
CAUSE
=====
Windows NT 4.0 Service Pack 6 addressed an issue where a user-mode program could
request more physical memory than what is actually installed on the local
computer. This could prevent the non-paged pool from expanding, and this can
cause the system processes to run out of memory.
RESOLUTION
==========
A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem.
To resolve this problem, contact Microsoft Product Support Services to obtain the
fix. For a complete list of Microsoft Product Support Services phone numbers and
information on support costs, please go to the following address on the World
Wide Web:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.
The English version of this fix should have the following file attributes or
later:
Date Time Size File name Platform
---------------------------------------------------------------
11/03/2000 05:31p 956,672 Ntkrnlmp.exe Intel
11/03/2000 05:30p 936,384 Ntoskrnl.exe Intel
11/03/2000 05:27p 1,409,216 Ntkrnlmp.exe Alpha
11/03/2000 05:27p 1,385,216 Ntoskrnl.exe Alpha
STATUS
======
Microsoft has confirmed this to be a problem in Windows NT 4.0 SP6a.
MORE INFORMATION
================
WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.
The memory manager in Windows NT 4.0 Service Pack 6 allows for non-paged pool
memory to grow to its maximum size before allowing a program to increase its
minimum working set size. For additional information about calculating non page
pool memory, click the article number below to view the article in the Microsoft
Knowledge Base:
Q126402 PagedPoolSize and NonPagedPoolSize Values in Windows NT
By reducing the maximum size of the non-paged pool, programs will be able to
receive a larger working set size. The non-paged pool can be reduced by
configuring the following new NonPagedPoolMaximumPercent registry entry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory
Management
Value Name: NonPagedPoolMaximumPercent
Data Type: REG_DWORD
Radix: Decimal
Data: 0 or 5 - 80
0 = Keeps the old behavior (default)
5 - 80 = The percentage of RAM that is allowed to be non-paged pool.
It is important to understand that excessively reducing the size of the non-paged
pool may prevent Windows NT from functioning correctly. If the non-paged pool
becomes exhausted, Windows NT generates Stop error messages. The Stop errors
that are most likely to occur if the non-paged pool becomes exhausted include
Stop 0x4D NO_PAGES_AVAILABLE, Stop 0x41 MUST_SUCCEED_POOL_EMPTY or other Stop
error messages.
If the NonPagedPoolMaximumPercent registry value is to be modified from the
default value of 0, you should determine the current non-paged pool usage. You
can do so by monitoring the following memory counter with Performance Monitor
over a period of time. Examine the counter memory / non-paged pool, and find the
maximum size it grows to. Use this as the minimum size the non-paged pool should
be set to. However it would be strongly recommended to allocate more non-paged
pool memory to allow for system usage changes.
The problem with a reduced working set size is very unique, and unless a program
requests an increase of its minimum working set size very significantly this
problem will not be noticed.
Additional query words:
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Keywords : kbenv kbtool kbWinNT400PreSP7Fix
Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400sp6 kbWinNTS400search kbWinNTSEnt400SP6a kbWinNTW400SP6a
Version : :4.0,4.0 SP6,4.0 SP6a
Hardware : ALPHA x86
Issue type : kbbug
Solution Type : kbfix
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