How to Set the Kernel Threads Registry Value
The Kernel threads registry value is the number of platform threads that handle the Presentation and Session level of the Open Systems Interconnection (OSI) stack. These threads are at the heart of MTA message processing.
If this MTA communicates with many other Exchange 5.5 servers using RPC over slow or highly latent network connections, it is recommended that you use a value listed in the following table.
| Value | Description |
|---|---|
0x3 (hex) |
Standard recommendation. Use this for any MTA that communicates with other Exchange 5.5 servers using RPC over slow or highly latent network connections. |
0x8 (hex) |
Use this for Exchange 2000 Server or Exchange Server 2003 MTAs that belong to a Site containing more than 15 Exchange Server 5.5 computers. |
0xC (hex) |
Use this for Exchange 2000 Server or Exchange Server 2003 MTAs that belong to a Site containing more than 30 Exchange Server 5.5 computers. |
In smaller organizations, the MTA process typically does not require manual tuning. After you have converted to Native Mode, you should remove these registry settings. Using the MTA tuning described below in a Native Mode Exchange organization decreases the performance of Exchange.
Before You Begin
Before you perform the procedure in this topic, be aware that the procedure contains information about editing the registry.
Warning
Incorrectly editing the registry can cause serious problems that may require you to reinstall your operating system. Problems resulting from editing the registry incorrectly may not be able to be resolved. Before editing the registry, back up any valuable data.
Procedure
To Set the Kernel threads Registry Value
Open a registry editor, such as Regedit.exe or Regedt32.exe.
Navigate to HKLM\System\CurrentControlSet\Services\MSExchangeMTA\Parameters.
In the right pane, locate and double-click Kernel threads.
In the Value data field, enter the value that is appropriate for your organization and click OK.
Close the registry editor and restart the Microsoft Exchange MTA Stacks service for the change to take effect.
For More Information
For information about how to edit the registry, see Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).