When a 7mb HTM file is first opened (by clicking on the file icon or using Open With), both IE8 and Firefox display this browser file quickly. After the file is closed, Firefox will reopen this file quickly, but IE8 appears to hang during the reopen. Clearing the IE cache does not help.
However, IE will reopen the file quickly again only if the File/Open/Browse feature of the menu bar is used (clicking on the file icon can be used only once between computer reboots).
Testing suggests that the problem relates to the number of HTML hyperlinks pointing to another part of the file. There are many hyperlinks, but they are not a problem during the first load of the document (between computer reboots).
What needs to be fixed to avoid use of the workaround? Using Windows XP SP3
Update 6/23/12 -
Controlled testing shows that the number of hyperlinks is not the problem. The way this large file is opened is the difference: 1) from the IE menu bar, File/Open/Browse is consistent and fast (but not as fast as FF). 2) clicking on the file name in the folder (even when IE is the default program for this file type) causes a much delayed load of the file. Creating a smaller file demonstrates the delayed load, but verifies that the load eventually occurs.
