This rule tracks the impact of .NET Garbage collector on the application performance.

Poor memory allocation/usage patterns can cause severe Cpu overhead coupled with frequent, significant processing pauses while the Garbage collections are in progress.

Why is this important

The GC is probably the biggest overall system factor affecting .NET application performance. Because .NET applications do not have direct control over memory usage, most applications are developed without particular consideration for how memory usage affects the application.

In reality, application design with respect to object allocation and usage can have a severe impact to its performance, both in terms of memory requirements and Garbage collector overhead.


This rule tracks the overhead of Garbage collections, measured primarily as the % of the application processing time spent in GC activity. The rule also tracks the kind/number of garbage collections, and allocation rate.


Diagnostics are coming soon. In the meantime, use Memory diagnostics to reduce GC overhead.

Improving the score

Improving GC performance is a complex task that includes both local optimizations using the Memory diagnostic data, and changes to application design. This rule will attempt to identify the issues that cause poor GC performance in the application.

Use the cause(s) identified by the diagnostic for additional information as to the types of issues affecting your GC performance, and the associated recommendations as a guide for making improvements.

Contact us for additional assistance.

Proactive guidance

If you are on a Business plan, we may offer additional support to help you optimize your application, please contact support to find out more.

More resources

Want to learn the best techniques for managing your IIS web server? Join our how-to newsletter.
Want to get the best tool for troubleshooting and tuning your web apps? .

Build your skills

Get performance best practices straight from our IIS & ASP.NET experts:

How-to newsletter: 1-2 emails/week with expert IIS & ASP.NET tips.