C# Mem Usage In Task Manager - Looks Wrong?

I have an app which ProcExp shows as having 500MB of private bytes assigned to it - This is about right as the app does a lot of data processing

When I see the same process in task manager it report 20MB of usage which is clearly wrong

Why would that be 开发者_开发知识库the case?

You're probably seeing the Private Working Set of the process in Task Manager (the default view). What you may actually want to look at, however, is the Working Set and/or the Commit Size, rather than just the Private Working Set.

You can change this under Vuew > Select Columns, and selecting the appropriate checkboxes.