DOCUMENT:Q237187  30-SEP-1999  [exchange]
TITLE   :XCON: Excessive Context Switching During Heavy Message Traffic
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5
OPER/SYS:
KEYWORDS:exc55 EXC55SP3Fix

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The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 
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SYMPTOMS
========

During heavy X.400 message traffic, the message transfer agent (MTA) may perform
excessive context switching, which causes X.400 messages to be delivered more
slowly through the Exchange Server computer. Context switching can be monitored
using the following Performance Monitor counter:

   Object: System
   Counter: Context Switches/sec.


RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Exchange Server
version 5.5. For additional information, please see the following article in the
Microsoft Knowledge Base:

   Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5. This problem was first corrected in Exchange Server 5.5 Service
Pack 3. When you apply the fix, the following registry key is created:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging
   Subsystem\Applications\EMSMTA

The following registry value is created under the above key:

   Value Name: UseMHEAPMgr
   Data Type: REG_DWORD
   Value: 1

Additional query words: throughput slow performance exchmem

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Keywords          : exc55 EXC55SP3Fix 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : winnt:5.5
Issue type        : kbbug
Solution Type     : kbnofix

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