Certain Websites really slow (Facebook, LinkedIn, flickr) others fine

I am running 64 Bit Windows 7 Professional, since nearly since the beginning some web pages that seem to use the same technology run very very slow and don't display properly. The most commonly known sites would be facebook. linkedin and flickr, although many other pages that I need to use are affected.
I tried installing different Java, change all kind of settings etc. All other devices on the network (Windows XP, Ubuntu, Andriod) are fine, so I can rule out the router. The computer is a dual boot (Windows 7 / Linux), on Linux everything is fine.
I also use different browsers (IE / Chrome / Firefox), all 3 of them having the same issue on Windows 7.
All "normal" web pages are fine without any issue.
Anyone came across that problem before and has a solution? I did all kind of virus checks and ran all sorts of speed optimisations with zero success.
It's driving me crazy, not the 3 pages mentioned, I can live without them, but I need other pages for work and have to work from 2 computers to be able to access them ...

When I go to facebook.com the site opens pretty fast, however when I click on the notifications and then on and image I get the loading animation endlessly.