The AspProcessorThreadMax property specifies the maximum number of worker threads per processor that IIS may create.
This setting can dramatically influence the scalability of your Web applications, and the performance of your server in general. Because this property defines the maximum number of ASP requests that can execute simultaneously, this setting should remain at the default value unless your ASP applications are making extended calls to external components. In this case, you may increase the value of AspProcessorThreadMax. Doing so allows the server to create more threads to handle more concurrent requests. The maximum for this property is 100 unless you change the value of the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ASP\Parameters\ThreadMax registry entry.
If the value of this property is changed, the Web server instance must be stopped and restarted for the change to take effect. The World Wide Web Publishing Service (WWW service) setting for this property is applicable to all in-process and pooled out-of-process application nodes, at all levels. Metabase settings at the Web server level or lower ignores in-process and pooled out-of-process applications. However, settings at the Web server level or lower are used if that node is an isolated out-of-process application. For more information, see Tuning AspProcessorThreadMax.
This property is a process-level property.
You can configure this property at the following locations in the IIS metabase.
IIS Admin Object Type
Client: Requires Windows XP Professional, Windows 2000 Professional, or Windows NT Workstation 4.0.
Server: Requires Windows Server 2003, Windows 2000 Server, or Windows NT Server 4.0.