How to Turn off AutoCAD Hatch Preview
To switch off the interactive hatch previews in AutoCAD 2011 onwards set the HPQUICKPREVIEW variable to Off. This will prevent roll-over highlighting of enclosed areas as you move the cursor around the drawing whilst running that hatch command. (can cause problems with large drawings or slow computers)
To change the settingof the HPQUICKPREVIEW, type HPQUICKPREVIEW on the command line then type 0 or off.
The variable HPQUICKPREVTIMEOUT (AutoCAD 2012 onwards) limits the time AutoCAD will take to create the hatch preview, reduce the value to suit your requirements.
The full list of Hatch Variables can be found here