I have a Gateway PC that has a Pentium 4 processor that uses
hyper-threading. The manufacturer advertised the machine as operating at
2.8 GHz. What I think this really means is that there are 2 1.4 GHz
processors.

Most applications seem to make appropriate use of the hyper-threading, so
the PC is normally pretty quick. Unfortunately, Excel does not.

Some of the spreadsheets I work in are really large (40 MB or so), with lots
of array formulas. When one of these is recalculating, it takes a really
long time. If I start Task Manager and check the processor load, it tells
me that only 50% of the available duty cycle is being used -- all by Excel.
This leads me to believe that Excel is not using both processors.

Does anyone know if there's a way to force Excel to use all of the
processing capacity of this machine?

For what it's worth, I'm running Excel 2003 on a Win XP Home SP2 operating
system.

David