Hello pk,
I am glad you are looking into the problem.
1] It happens everytime I want to start an application, run the application or close the application... What I mean, after the system is fully loaded on and I want to use web browser, the actual start of the browser is slow as hell. Then, when it starts, every move in the browser is affected as well (i.e. loading pages, using shortcuts and even when I close the browser it takes around 15-20 second before it is shut down). Happens to most of the programs (skype, games, media players - music&video). But it doesn't seem to happen when I open some regular file, like on a desktop or in My Computer.
2] That actually seems to be helping. I will test it more to see if the difference prevails or not and let you know by the end of the day
3] How do I see that it scans those files or not?
EDIT: Disabling the reputation services partly helped, it's better then with this option enabled, but the system isn't still as fast as with the shield turned off completely.