ATTROLL here's my two cents...
Attrol et al, here is my two cents worth and may also help shed some clues for you.
I have noticed on certain days or times where the pages seem to load as explained (largere than the window). Then a few seconds sometimes nearly a minute later it corrects itself and everything is fine.
My thoughts are this, possibly the server you are using is having some issues at certain times and so the pages are not sending all of the packets thru as they normally do. Yes, browser and other things can affect the issue but you may also want to consider the server and just the web itself.
It could be a chokepoint in the systems on one end or the other where the bandwidth is not large enough and so you get some fragmentation of the info so that the page loads as it should.
Time of day can affect how things happen also. Because as we all know there are times when usage of the web is higher and times when it is lower.
Yes what browser (compatibility), Forced resolution issues and such are also issues which can cause the problem.
Again from time to time I also see this and it generally corrects itself (yes on both forums) in a moment. BTW I'm on a Cable line. So while it's not a T1 it's also not a dial-up either. That's part of the fun of keeping up a webpage.
That's my two cents for what it is worth!
Touch of Grey