How to limit CPU usage in IIS

Overview

If you are using a 3rd party .NET application in IIS, sometimes it can be beneficial to limit the CPU usage to stop the application using all available CPU. On most operating systems and especially Windows Server, if all available CPU is used services will respond slowly and some will not respond at all.

This article will take you through the process of limiting the amount of CPU an IIS application can use.

Instructions

1. Use Remote Desktop to access the Server:
   
2. Open the Start menu and search for IIS.
3. Once found, open IIS Manager:
   
4. Click Application Pools:
   
5. Right click your applications Application Pool:
   
6. Select Advanced Settings:
   
7. Under CPU set Limit (percent) to a value below at least 80%
   We recommend 60% in most instances) to ensure enough CPU is available for the Windows:
   
8. Under Limit Action select Throttle:
   
9. Next set the Limit Interval (minutes) to 10.
   This will give the process 10 minutes before it is checked again for overuse:
   
10. Click OK:
    
11. If you have multiple applications that work in Sync on the same IIS server, you should repeat the above steps to ensure all processes are limited.
12. You can now close IIS Manager.

We recommend monitoring your applications closely to determine if throttling is severely limiting performance. If you find the application runs slowly when throttled you may consider stepping up the Limit (Percent) value closer to 80%.