DIFFERENCE BETWEEN FREEZE AND TURN LAYERS OFF IN AUTO CAD

From outside you cannot identify the difference between
FREEZE and TURN LAYERS OFF.  If you Freeze a layer 
then its contents are not displayed.  And Similarly if you
turn off layer, its contents are not displayed.  Only 
difference between these FREEZE and TURN LAYERS OFF
is in display Memory.  When a layer is frozen the information
required to display it on screen is not loaded onto your
graphics card memory.  And when a layer is turned off,
all the information required to display the entities on that 
layer is loaded into your Graphic's Card's Memory.

if you turn off a layer, you get slower panning and zooming
on large/ complex drawings.

If you Freeze a layer, you get faster panning and zooming.