Maoni (which has a great blog that I’d recommend everyone to read) posted a set of posts (first, second and third – 3 so far…) about what the difference between performance data reported by different tools and what does it actually mean.

When you use a tool that collects performance data (or any data for that matter) you should always be aware of how this data is being collected and what does it say in the context of that tool.

Manoi does a fine job and describing numerous tools such as perfmon and WinDbg (with the use of the SOS extension).

See my previous post “Perfmon – Your debugging buddy” for some information about how various .NET counters can help you debug your application.