[Qt-interest] Calculation in Thread extremly slow

[Matthias Pospiech]

I have a time consuming calculation, which is mainly doing FFTs and 
memcpy operations.

It was first implementent within the dialog class and thus within the 
GUI Thread. In Release mode it could do 500 Calculations in less a second.

Now I have moved it to a separate thread which is included as a pointer 
in the dialog class. The result was that it takes almost a minute to do 
the same calculation in release mode. So it is 10 to 100 times slower.

Any principle C++ / Threading thing I could have done wrong ?

Matthias