Problem: Opening ArchiCAD 12 Help file in Internet Explorer 8 is very slow.
The blue-white background rolls down very slowly, even moving the IE's window is very slow.
Solution: This problem is caused by the ArchiCAD help htm page background scheme. Just set the full page zooming to 100 % and everything works fine. You can also use the option of reset zooming level to original size at opening new windows and tabs in the Tools/Internet setting/Special tab.
What to do if you want to zoom? Well, you can use the option omitting web page colors at Tools/Internet setting/General/Lower right button/
I wish someone could modify the Help background htm page deleting this blue-white background...