currently I am testing a WPF application, which is has a simple architecture but is dealing with a lot of data. There is now web service or anything. Just the application and a connection to a Oracle database. We tested this software with a single user scenario and multi user.

But now we encounter that some customers have huge performance issue. We couldn't reproduce this until one of our colleagues also got the same performance issues. It seems like the application is just hangs up at simple task like searching. Normally this take the application to take 4 seconds. But with this special computer it takes 30 seconds and more.

We already checked this with dotTrace and we saw that our application is processing for 4 seconds and then for the rest of time an unmanged code is running. After this the result is displayed. This made us think about the possibility that maybe another process is preventing our application to run like expected.

Talking about the requirement "performance" is always a case of specification. We want our application so fast and responsive like the old win client application. We made a complete makeover with WPF from WinForms with a better UI and more help sections for the users.

Because I am not familiar with performance testing, I am asking you guys what to look for. I already installed the CLRProfiler and checked the Heap for memory leaks. Also I found some articles about perfmon but I couldnīt figure out how to used it for my task.

The application, is like mentioned above a WPF desktop application, which gets his data from a database. When using task like searching or opening a data set it is very slow. But also other task are really slow to, like opening some menus. But this is just reproduceable on one PC in our company.

I thank you for every reply.