When you host Web applications that use Microsoft ASP.NET on a computer that is running Microsoft Windows Server 2003, you may experience decreased performance. This issue may occur when you host the Web applications in multiple application pools on a multiprocessor computer. Additionally, you may experience one or more of the following issues when available memory is low:

•	You may receive exceptions of type System.OutOfMemoryException.
•	You may receive the following error message when you try to open an ASP.NET Web page: Server Application Unavailable
•	The computer may stop responding.

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These issues occur because the Microsoft .NET Framework common language runtime (CLR) uses the Server garbage collector (GC) on multiprocessor computers. This is the default behavior. The Server garbage collector is optimized for scalable throughput on multiprocessor computers. To reduce contention and to improve garbage collector performance on multiprocessor computers, the Server garbage collector creates one heap per processor for parallel collections. Therefore, the Server garbage collector consumes lots of memory when you host multiple ASP.NET worker processes. This behavior may cause the issues that are described in the "Symptoms" section.

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To work around these issues, configure the .NET Framework common language runtime to use the Workstation garbage collector. The Workstation garbage collector is optimized to reduce garbage collector pause times for interactive applications. Additionally, the Workstation garbage collector creates only one heap. Therefore, the Workstation garbage collector uses less memory when you run applications on multiprocessor computers.

To configure the .NET Framework common language runtime to use the Workstation garbage collector, add the following code after the <runtime> element in the Aspnet.config file. The Aspnet.config file is located in one of the following folders:

•	If you are running the Microsoft .NET Framework 2.0: %WINDIR%\Microsoft.NET\Framework\v2.0.50727
•	If you are running the Microsoft .NET Framework 1.1: %WINDIR%\Microsoft.NET\Framework\v1.1.4322

<configuration>
<runtime>
<gcServer enabled="false"/>
</runtime>
</configuration>

Note The Workstation garbage collector is optimized for low latency. Low latency is typically required for client applications. However, low latency may cause decreased throughput after you configure the .NET Framework common language runtime to use the Workstation garbage collector.

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This behavior is by design.

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For more information about performance considerations in the .NET Framework, visit the following Microsoft Developer Network (MSDN) Web site:

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