Perhaps “Sleep” or “Standby” is the one of the most useful computer features invented for home users. Sleep lets you put your laptop / computer into a low power state for some indefinite period of time, and then resume work quickly without the annoying wait involved in booting your computer from scratch.
Most laptop users boot their laptops only occasionally; normally we put our laptops to standby every night and resume work quickly in the morning. Sleep keeps all your running programs and even the operating system in the main memory, but shuts down as much of hardware as possible.
In order to keep programs in the main memory, your laptop consumes a small amount of power that drains your battery while it is in standby mode. This power consumption can be anywhere between 1 watt to 3 watts. Moreover, when the operating system (like Windows or Mac OS) detects that your laptop battery has reached a critical limit, it dumps the contents of your entire memory on the hard disk, and puts your machine to hibernate state. This helps preserve the state of your work, and lets the laptop enter the zero power consumption state. However, your laptop takes longer to resume from standby, since the contents of the main memory have to be read from the hard disk, which is much slower than the main memory.
However, did you know that Windows also supports something called Hybrid Sleep in addition to the default Sleep operation. What the Hybrid Sleep operation does is that in addition to putting your laptop in a low power mode, it also dumps the contents of the main memory to the hard disk every time you put your computer to Sleep.
Normally, the Hybrid Sleep option is turned off by default, but you can always turn it on in the advanced power settings. This is usually not required, unless your laptop battery is very old and discharges suddenly (without giving Windows enough time to respond to the low battery event). This option will also help you if you have a spare battery and you sometimes swap the batteries while your computer is in standby. In either cases, when you turn the power on, Windows will be able to resume your work and data from the copy of the main memory that resides on the disk.
Neat, isn’t it?