What's the Difference Between Standby and Hibernate? (From: http://www.tipsintime.com/84.htm)

What's the Difference Between Standby and Hibernate?
In Standby mode, power is saved by shutting down the hard drives, fans and monitors. These are high power consumption devices. The computer still uses power to save the data in memory, so you can restart very quickly (however, if power goes off while in this state, the data in memory will be lost).

In Hibernate mode, XP saves the data in memory to the hard disk. Then the power is cut off completely, so this preserves more battery life. When you restart, it takes a little longer because the data saved on the disk must be restored to memory. Of course, this method uses disk space to store the memory data.

If you're using the XP theme view, you might not see the Hibernate option when you select to shut down the computer. First try holding down the Shift key to cause the Standby key to change to Hibernate. If that doesn't work, hibernation might not be enabled. Go to Control Panel | Performance and Maintenance | Power Options (or just Power Options in classic view). On the Hibernation tab, check the box that says Enable hibernation and click OK.

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http://www.tipsintime.com/84.htm

What's the Difference Between Standby and Hibernate? (From: http://www.tipsintime.com/84.htm)