idle-update-delay

idle-update-delay is a variable defined in `simple.el'.
Its value is

0.5

Documentation:
Idle time delay before updating various things on the screen.
Various Emacs features that update auxiliary information when point moves
wait this many seconds after Emacs becomes idle before doing an update.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.