Hi,
Avast 7.0.1456 was slowing the web browsing using MS internet explorer 9 on my machine(win7 64bit), and really alot. Not sure when it started. Tried many settings, and this helped me:
I had to partially disable Behavior shield (expert settings - monitor the system for unauthorized modifications).
Just wanted to let you know in case someone has the same problem, what could maybe help. Hope it will be fixed in future. Swithing off security is not the best solution :-D.
Michal