When this issue occurs, each character takes more than one second, even though the spell checking feature is disabled in Internet Explorer 11 in Windows 8.1 or Windows 7.
To fix this issue, 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 the Description of the cumulative security update for Internet Explorer: September 8, 2015 (MS15-094).
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.