Hi There

I need to add some User Defined Functions to Excel 2003 - the functions are
CPU intensive.

The existing spreadsheet has the functions written in Excel VBA (as an XLA
add in), and they are very slow.

What are my choices ? Is this correct:
(1) Write an XLL in C++
(2) Write a COM Add in in C++
(3) Write a COM Add in in C#
(4) Write an Automation Add In in C#

Has anyone done any comparisons on the performance of XLL's in C++ versus
Automation Add Ins in C# ? I suppose C# is a great deal slower because of
the Interop ?

TIA