After the page has loaded there is period in which IE, both 6 and 7, locks up. The page has already loaded but there is some kind of pre-processing taking place.
If this were to happen on the first load of the site only and subsequent loads were unaffected then it would be acceptable. Firefox has a delay but it is tiny and acceptable.
I have been trawling through the documentation but can find no mention of this, how can this delay be removed or contained to first load only?
Here is a video
demonstrating the problem.