Go to terminal, type this command line

pmset -g | grep hibernatemode

The result will be either of the following

• 0 = normal sleep for desktop (save in memory. use low power)
• 1 = hibernate (save in hard disk. total off)
• 3 = safe sleep (save in memory and hard disk. use low power)

To change, type this command line,

sudo pmset -a hibernatemode X

(X to replace with either 0, 1 or 3)