Hi everyone,
I've got a bit of a strange one here, I'm still investigating but thought I
might post in case anyone has any ideas.

We have a quite complex spreadsheet (Excel 2003) where the speed of
calculations had started to become an issue.

Upon investigation of the speed issues it became apparent that most of the
time, when performing the calculation operaton (either automatically or by
pressing F9) a network spike would show in the LAN section of the
'Networking' tab in Task Manager. This spike appears only when calculating
and drops back down to 0% as soon as the calculation is complete.

This spreadsheet is running completely locally (C drive). There are no links
to spreadsheets anywhere on the network.

We found that if you unplug the network cable, then the calculation speed is
only a fraction of the time, and obviously there is no network activity
showing in the task manager.

To add further confusion to the problem, it does not appear to happen every
time. There are times (so far they seem random, but I'm still looking for a
pattern), where you open the spreadsheet and calculation is fast, and no
network activity is present.

Due to the fact that this activity perfectly coincides with the calculation,
I don't believe this has anything to do with any software updates from other
applications.

Any help/ideas/advice would be welcomed.