I got this response from endnote tech support.  A strange
solution, and
probably one I won't follow through with myself, but if
anyone is
interested in trying it, here you go.

allie




Hello Alex,

[edit] so I will offer you a potential solution.
In Word 2003, under Tools - Options - Edit (tab), there
should be a
"Keep track of Formatting" option.  If this item
is turned on, it's
entirely possible that EndNote will become a
"hog", mostly due to the
Traveling Library codes present in the document.
If this option is turned off, this will often result in
decreased
memory/CPU usage.
Please let us know.