Suspend to RAM to save power

Today is Blog Action Day, and so I thought that I would write a bit about how I save energy while still maintaining an (almost) always on computer.

Every modern computer supports Suspend to RAM, but in my experience, few people use it. Most people either leave their computer on all of the time for convenience or turn it off when they are done with it in order to save power. Suspend to RAM allows you to have the best of both worlds very little power usage when it is suspended and instant availability when you are ready to use it again.

Basically, when your computer enters the Suspend to RAM (or goes to "sleep") everything inside the computer gets turned off except for the memory. This includes all of the fans, hard drives, video cards, etc. For all intents and purposes your computer will appear to be off except for possibly a small light somewhere on the computer that blinks to show that the computer is still on. When you wake the computer back up again, everything should appear exactly as it was before the computer went to sleep in less than 5 seconds.

Here are some simple tips on how to get started using Suspend to RAM mode on your Windows PC:

1. Open the "Power Management" control panel icon (Start->Run->"powercfg.cpl" works too)
2. Adjust the System Standby time to match your needs.
3. I prefer to put my computer to sleep and wake it up with the power button. I want to enable this function, then click the "Advanced" tab and change the "When I press the power button on my Computer" setting to be "Standby".

Now you should be all set to go. Your computer should go to sleep after a short period of time, and it will wake back up when you press a key on the keyboard or press the power button on the computer again.

Unfortunately there are a lot of things that can go wrong with this process. The most common problem that I have encountered is that the computer doesn't shut down completely and the fans and hard drives are still running. In this case doing one of the two following tricks normally fixes the problem:

• Disable the "Allow this device to bring the computer out of Standby" setting for all of your USB devices.
• Right click on "My computer and select "Manage", then open the "Device Manager" (or Start->Run->"devmgmt.msc")
• Double click on the device to bring up the properties window
• Make sure that "Allow this device to bring the computer out of Standby" is not checked in the "Power Management" tab
• Change the power scheme to "Portable/Laptop"
• Open Power Options in the Control Panel (or Start->Run->"powercfg.cpl")
• Change the Power Scheme to "Portable/Laptop"
• Check to see whether the fans still run in Standby
• If the problem is fixed, then you should be able to change the Power Options to custom times without a problem.
• This solution may seem a little bit sketchy since it doesn't seem to change anything that you couldn't change already, but there is definitely something that gets reset with this hack. I once had a machine that wouldn't sleep properly and using this hack fixed the problem.
  

If you need more help, there are a couple of people with more detailed writeups that you can follow: (exoid.com) (jillesvangurp.com) (thegreenbutton.com)

So how much power does this actually save? On my desktop, which I consider to be fairly average, I used a Kill-A-Watt meter to measure the power draw of my computer. While running, the machine uses ~150 Watts. If I suspend the machine, then I only draw ~8Watts. For a 24-Hour period that is a savings of about 3.4 KW-Hrs!