Registry Size Limit Change Results in PagedPoolSize Change

• Microsoft Windows NT Workstation versions 3.51, 4.0
• Microsoft Windows NT Server versions 3.51, 4.0
• Microsoft Windows 2000 Professional
• Microsoft Windows 2000 Server
• Microsoft Windows 2000 Advanced Server

SYMPTOMS

When changing the registry size, the entry for PagedPoolSize may be automatically changed from its default setting of zero to a fixed value. This could result in unexpected and or undesirable behavior on a Windows NT server.

CAUSE

The registry is not allowed to consume more than 80% of the Paged Pool. If you adjust the Registry Size Limit (RSL) in the Virtual Memory dialog box in the System section of Control Panel to a value greater than 80% of the current PagedPoolSize setting, the PagedPoolSize registry entry is automatically changed from the default setting of zero to a value equal to 125% of RSL.

NOTE: For both Windows NT 3.51 and 4.0, the PagedPoolSize registry entry is set to zero by default in Setup. When this registry entry is set to zero, the actual PagedPoolSize is calculated dynamically based on your current memory configuration. Under Windows NT 3.51 prior to Service Pack 4, the resulting field value from an RSL change could be lower than the one dynamically calculated. For Windows NT 3.51 after SP4 and for Windows NT 4.0 the zero will be maintained if the calculation for paged pool based on the physical memory is larger than the calculation based on the registry size limit.

For additional information on PagedPoolSize, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q126402
TITLE : PagedPoolSize and NonPagedPoolSize Values in Windows NT 3.5

WORKAROUND

Depending on the increase in RSL you can reset the pagedpoolsize back to zero in the registry. A rule of thumb would be to use the amount of memory as a benchmark for the amount of pagedpoolsize created dynamically and if the new RSL is less than 80% of that value then it is probably safe to set pagedpoolsize back to zero.

These values may be modified in the registry.

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

The pagedpoolsize parameter is located in:

   HKEY_LOCAL_MACHINE
     \SYSTEM
       \CurrentControlSet
         \Control
           \Session Manager
             \Memory Management 

RESOLUTION

This problem has been corrected in the latest Service Pack for Windows NT version 3.51.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.51. This problem was corrected in the latest Windows NT 3.51 U.S. Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: 3.51 prodnt

Keywords : ntconfig
Version : WINDOWS:2000; winnt:3.51,4.0
Platform : WINDOWS winnt
Issue type :