Save energy by using computer's stand-by mode

Idle computers should be set to automatically switch into stand-by mode after extended periods of disuse. Stand-by mode protects the computer's components and helps them last longer.

It can also cut electricity costs, reports PC Professional magazine. Presuming one has an office computer that remains unused for three hours a day over the course of 225 working days a year, stand-by mode can save almost 100 kilowatt hours (kWh) in electricity, the Munich-based magazine has estimated. At electricity prices of between 15 and 20 cents per kWh, that can add up to between 15 and 20 dollars per year.

The magazine recommends using the so-called S3 mode. That instructs the computer to store an image of the memory and processor register from the current session in the RAM. All components other than the RAM are then separated from the power supply. The system does not need to be rebooted during wake up, but instead restored to the last state from the memory.

The tests showed that the process lasted only six to 10 seconds. The alternative S4 mode works in a comparable way, although the system image is stored on the hard drive and the system is completely turned off. Waking up the system takes at least 20 seconds because it needs to be read from the hard drive, a slower process than reading from memory.