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How to reduce the amount of power your computer uses.

I probably don't need to tell you that these are tough times right now. Many people are taking a hard look at how they can reduce their utility bills. One item that has come under scrutiny is your personal computer. In fact you can reduce your computer's power consumption through a feature called ACPI
(Advanced Configuration and Power Management)

So how do you reduce power consumption?

To take advantage of ACPI you can use the power consumption applet built right into Windows. To access power management features click on your Start Menu then Control Panel one of your applets should be Power Consumption and it looks like this! Power Save Icon

Once you click on this icon you should see something like this (If you are using Windows Vista this might be different.)

Power Save Screen 1

Power Schemes - These are predefined configurations for your computer. Laptops will see 2 columns this allows laptop users to configure different settings for battery power.

Turn off monitor - This will put your monitor in a power save state after the configure timed. Your monitor will go blank and you will typically have an amber blinking or solid light on your monitor telling you of its status. According to the US department of energy this should be configured for 20 minutes. This may need to be set for Never if your monitor has problems recovering from this state. It takes approximately 10 seconds for your monitor to recover from this state.

Turn off hard disks - Even though you may not be accessing your hard disk your disk continues to spin this is so when it does need to access data it can respond faster. This feature will cause your Hard drive to spin down after the allotted time. When the computer wakes up you can often hear the drive spin back up and your computer will be unresponsive for approximately 10 seconds. The US department of energy recommends this be set to 2 hours. You may need to set this for never if you computer performs tasks during it's idle time. These tasks include virus scanning, online backup and various other indexing tasks as these tasks may not get done if the drive is powered down.

Configuring these two options can give you an energy savings of up to 40%

System Standby - This state powers down nearly everything on the computer. Only the RAM and one or two other things are left running. This state will reduce your computers energy consumption by over 90%. Though the US department of energy does not have a recommended setting. I recommend 2 hours. This feature is very useful if you have a Laptop running on battery power. If you do use it in this scenario your system standby should be configured for 20 minutes. If your battery still drains too fast then reduce it to 10 minutes. This feature should not be used if your computer performs tasks such as backups, updates or virus scanning during it's idle time. Wake up time for a computer on stand by can take as long as 30 seconds there is also a 1%-2% chance that the computer will not recover from standby mode. If this occurs you will lose all unsaved information and you will need to power down your computer and restart.

Lets move on to the advanced tab

Power Save the Advanced Tab

Always show icon on the task bar - If this button is selected you will have an icon in your task bar (next to the clock.) that resembles the power options icon. If you mouse over this icon it will tell you how long you have before you need to plug it in and whether it is charging or not. This is useful on a laptop as it will show you how much life you have in your battery and when it is fully charged. However the icon adds no benefit when used on a desktop so desktops usually have the option disabled.

Prompt for password when computer resumes from standby - If your computer is password protected this will require you to enter your password to get back into your computer when it wakes up from standby.

Power and sleep button functionality - If you are wondering what your sleep button is it is usually a key on your keyboard that has a moon or a line of z's for an icon. This button allows you to manually put your computer in standby mode (or whatever you program it to do.) You have four options on both of these items Do Nothing, Ask Me what to do, shut down and stand by. All of these functions are self explanatory or I have covered what they are previously.

The Hibernate Tab

The Hibernation Tab 

Up till now we have covered 3 of the 4 states of ACPI. The final state is hibernate. This state writes what is in RAM to disk and shuts down everything. Hibernation mode takes as much power as a computer does when it is turned off (About 2W) but since the computer has already 'booted' this can result in less load time before it is ready for use. A computer can take 1 minute or more to wake up from hibernation mode but is usually faster then loading the computer from the off state. Computers will fail to come out of hibernation mode as much as 10% of the time. If it does all unsaved work will be lost and you will need to do a complete power cycle of the computer. This can be done by holding the power button for 5-10 seconds on the front of your computer. Since this state is the same as if the computer is off your computer will be unable to do anything while in hibernate mode. You should also make sure you save your work before it enters hibernate mode in case it does not recover.

Enable hibernation - This will add hibernate functionality to the Power and Sleep keys on your computer as well as a hibernate timer on the Power schemes tab.

The UPS tab

The UPS Tab

A UPS ( Uninterruptible Power Supply) is an additional peripheral that you would plug your computer equipment into. A UPS will deliver the same voltage the computer regardless of the input voltage as well as provide power for a limited time in the event of a total power failure. They are used when power must be provided to the computer 'no matter what' such as the case with servers. UPS's are also a good idea if the power in your area is unreliable. Many UPS's come with their own software which will show up on this tab when installed.

100% savings

Like many electronic devices computers draw a trickle current even when they are turned off. This trickle power is about 2W (less than an incandescent nightlight). To truly get 100% power reduction your computer and monitor should be unplugged from the wall. You can also connect the equipment to a power strip or UPS and use the off switch on the power strip/UPS. All computers have a small battery inside that provides constant power to the computer to maintain fundamental settings such as the Date and Time so it is completely safe to unplug your computer.

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