...and reduce speed to .76 during cruise. Even when there are no recommendations in the manuals to set this speed for cruise phase of flight at any turbulence intensity.
Boeing AFM:
The recommended procedures for flight in severe turbulence are:
1. Air Speed
Target air speed should be approximately 280 KIAS or 0.76 Mach,
whichever is lower. Severe turbulence will cause large and
often rapid variations in indicated air speed. DO NOT CHASE THE
AIR SPEED.