Hibernation vs Standby Mode are very similar and easy to confuse the two. Standby turns off power consuming components like the hard disks and display. It switches the computer to a low power state. Standby maintains power to your computer's memory so you don't lose your work.

Hibernation saves state information by writing a hibernation file which contains the contents of memory and is thus the same size as total RAM. This is a snapshot of active memory. When you turn your PC back on, the state, including which applications are running (desktop) and the memory contents are restored to RAM and voila! - you are back to where you were when Hibernation mode started. The restoration of state can take place in 5 minutes, 5 hours, 5 days, 5 weeks, ….