Linked files extremely slow to save.

I have about 8 files that have links between themselves. Not always, but most
of the time if I have more than one of them open, when I go to save one, the
save process can take anywhere between 5 minutes and maybe up to hours. The
time may depend on how many of them I have open, rarely all of them at the
same time.
If I give up, when I go to task manager, they all show as not responding.

This is not a problem in Excel 2003 as it works fine, but in Excel 2007 it
can be a real pain if I forget to close all but the one I need open..

Any all help appreciated..