Internet Explorer 11 Loading delay with Advertisements?

[Laurence I]

any webpage that relies heavily on javascript, such as the Yahoo home page will have many issues.

using javascript allows parts of a page to load quickly and other parts to take as long as they take.
effectively what it means is although you THINK you are loading a single webpage, whats actually happening is you are MERGING data from MANY places when using ads.
each one of these ads, could potentially be coming from a different location, or even a different server.

things that affect your perceived performance are
1 your AV and how it deals with a page that is actively seeking a connection to many places
2 the way the page either TASKS each GET all in one go, or how each one may wait until the previous one is finished. So thats a more staggered approach to downloading it.
3 these sorts of webpages are often LIVE with webpage editors changing them on a LIVE basis. So the SCRIPT could have ERRORS that you are not SEEing. This means that visit them 5 minutes later and the errors may not be there any more, or be less of a problem.
4 keeping your browsing history(cache) regularly emptied may help.