When a computer is put on the hibernation mode, the computer takes a snapshot of all the memory contents and the computer settings and saves all this information on the hard disk of the computer. After the information is saved, the computer turns off. The advantage of putting the computer on the hibernation mode is that when the computer is restarted all the memory contents and the settings are restored to the time when the computer was turned off. A great benefit of this is that there is no need for power by the computer to maintain itself in the hibernation state unlike the standby mode.
Sleep mode typically will store activity in RAM and then turn off the monitor or hard drive, but not the power to the computer. When the computer comes out of the hibernation mode all the programs and documents are restored. However, turning off hibernation mode can save a lot of disk space. The amount of space it will save depends on your pc, but it could save gigabytes worth of space.
