EDIT: @TB Question: Exactly what is hibernate? I've never actually used it, never been game since a friend of ours told us that he enabled it and couldn't get his pc working for a week.
Well first I best tell you about the ACPI power states.
S0:The system is running fully but the monitor is off
S1:CPU stops processing data but remains powered, RAM is also has power, devices like HDD may get powered down
S2: CPU is turned off, HDD are off, RAM still has power
S3: This is also known as sleep mode. All data is kept in RAM, all hardware except RAM has no power
S4 This is also known as hibernation. All data in RAM is saved to the HDD and the PC is shut down, when powered back on data is reloaded from the HDD back into RAM.
S5:: This is a typical shutdown. All devices are powered down and it is safe to shut the PC down.
S6: This is a hard off. This is only done by switching the power switch to off on the PSU or pulling the plug.
As read in S4 hibernation is where all the data in RAM is saved to the HDD(in windows's case it is in the hiberfil.sys file.
If you have a SSD it is best keept off as the hiberfil.sys will be same size as your physical RAM size, so if you have 16GB of ram in an SSD machine the hiberfil.sys will be 16GB.
Besides hibernation is useless in an SSD bases system due to fast boot times or you could put the system into S3 mode and it will be back to where you left in seconds.