Suspend to RAM which is 'Sleep' on the shutdown menu, will power down various devices of the PC while retaining the OS in RAM.
If you power off then you lose everything.
Suspend to Disk which is 'Hibernate' on the shutdown menu, saves the current state to the Swap partition, thus allowing full power down, and when rebooted, will boot up the saved state.
Best suggestion I can give is to set the time outs for the various settings to 1 minute while you test to see if they are operational.
The functions and how well they work are dependent on your hardware as well as the kernel in use.