Recently upgraded from Excel 2002 to 2003, from Windows 2000 to XP, and from a
dual P4 to dual Xeon 5100, i.e. four cores. This is a big, fast machine.
But one sheet is running slower!

This particular sheet calcs in about 1 second with not much else running,
but
4-8 seconds when all windows (about 40 total) are open.
It is not short of CPU - task manager shows about 25% CPU usage, and in this
state Excel itself never goes above 10% CPU usage.
It is not short of memory - this machine has 4GB of RAM and around 2GB used.

I have looked at the network traffic and it doesn't seem to be doing file
I/O. The sheet does receive a lot of data from Reuters (via RtGet) but that
shouldn't change just because I opened some more windows.

Any ideas what it could be, or what to try?

Bryan