Hello there,I have a performance problem relating to Excel with a C++ dll. Here is my point:I compile a dll with a simple function ( such as: sum by a loop ) then I open Excel , launch a simple vb macro to call this function.I try to compare the elapsed time to run it with excel ( VB + dll ) and the direct runtime ( C++ exe ), so far it is almost the same.Now, I do the same but I change the function in my dll: I put a call to the math function log ( ie now I have a sum of log now ) .Now when I compare the excel way and the direct runtime way , I have a large gap between them: Excel is by far worse than the runtime ...If you have a clue of what's going on , I will be pleased to know it!Thx in advancePS: I have tried to cast any variables involved, it is better but I still can find this huge difference between Excel and direct runtime

bsv,Can you give us an idea of the difference in performance ?B.