Standby Suspend Sleep and Hibernate
What is the difference between sleep, standby, suspend, and hibernate?
Computers typically offer various power saving modes. The names for these modes will be something like standby, suspend, sleep, and hibernate. Typically the standby, suspend and sleep modes require that the computer be left on to some degree, and that it stay connected to power (battery or AC). While in these modes, the hard drive usually stops running, the display turns off, and the fans might even turn off. However, the computer is still keeping in active memory everything that was running and open just prior to being put in a low power mode. The hibernate mode allows you to turn off the computer completely and even unplug it from power. When it turns back on, the screen should show you exactly what you were were working on just prior to putting it in hibernate mode.
Because standby, suspend and sleep modes keep all the information in memory, it is typically quicker to start working again after being in these modes. Resuming work from the hibernate mode typically takes more time because it requires starting up the computer and loading everything into memory from the hard drive again (although you don't need to manually start the programs and load the files because the computer will restore everything to the state it was in previously).
Depending on the computer and configuration, some cleanup tasks may be performed at system startup and shut down. So, some people prefer to simply shut down a computer when the are done using it.
Some people suggest that it is best to leave computers on. However, if we consider the computer to be like any other appliance, then it makes sense to simply turn it off when it is not in use just as we would with a television set, dish washer, microwave, coffee pot, or any other appliance.