The decrease in performance affects quirks-mode table content in Windows Internet Explorer 8, Windows Internet Explorer 9, Internet Explorer 10, and Internet Explorer 11.
To resolve this problem, install the most recent cumulative security update for Internet Explorer. To do this, go to Microsoft Update. Additionally, see the technical information about the most recent cumulative security update for Internet Explorer.
Note This update was first included in March cumulative security update for Internet Explorer (MS15-018).
To work around this issue, you can set the content to be displayed in standard document mode.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
See the terminology that Microsoft uses to describe software updates.