Dear concreteinterface,
I doubt that Excel is supposed to work that slowly, or haven't you upgraded your machine since 1998? Try buying an i487 co-processor - that should speed up your Excel a bit.
Seriously, it seems extremely 'unsmart' to fill in that many formulaes with no actual content - and Excel is not used properly here. Better is to have them filled-in dynamically from VBA scripts, or even to have the calculations done within VBA and to have only the actual data stored on the spreadsheets.
If you don't know how (yet), try recording the manual sequence of copying a row with formulaes to the next row as a macro and start analyzing the code.
Good Luck!