I found this in the IE newsgroup:

If HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\AutoRefreshLocalPage is set to "yes" change it to "no"

And it'll stop the incessant re-downloading of images from pages that you just visited a couple of minutes ago. This actually makes IE4 perform quite well on a site like the UniversalThread where you spend a lot of time. Heck it might even make the MS website pages load faster. *g*