Standby Explained (S1, S3)

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Since I built my first do-it-yourself computer almost 2 years ago I was super interested in making sure that when the computer went to sleep (standby) it was silent. After all, what is the point of putting something into standby if the fans and HD were running?

Well, if you build your own PC, there are a number of factors that will determine if this is at all a possibility. First let’s start with a discussion of the different states your PC can be in.

S0 - Working State

In this state, your PC is awake and working

S1- CPU Stopped

In this state, your PC is technically in standby and this is the default standby state if S3 is not supported. Power consumption is Five Watts to Thirty Watts of Power.

S3 - Suspend to RAM (context saved to RAM)

In this state, your PC in standby and all fans, hard drivers and other devices are powered down into a sleep state. Power consumption is less than Five Watts.

S4 - Suspend to Disk(Context saved to HDD)

Otherwise known as Hibernate, your PC has saved the contents of RAM to the hard disk and is pretty much tuned off. Power consumption is less than Five Watts. This isn’t very useful for desktop PCees and is mostly used in Laptops where battery drainage is far better than if you are in S3.

Now, as I mentioned there are some requirements before you can use S3.

  1. Motherboard must support S3
  2. S3 support must be enabled in the BIOS (many motherboards do not do this and default to S1)
  3. OS must support S3 (Windows XP does)
  4. To wake your PC from S3 your USB peripherals (like keyboard and mouse) must be enabled to arm your PC to wake.
    1. From the device manager, you must select they keyboard, go to properties and select Allow this device to bring this computer out of standby. On a Windows Media Center you’ll want to do this for the Remote Control device.
  5. The following reg key must be installed.

Step number 5 is the most critical step of all. Not surprisingly, a post that I wrote back in April of 2002 is the most frequently visited page on my web site. I get hundreds of hits a month to this page from people doing google searches on dumppo.exe and other related standby issues. My guess is that they are all having the same problem I had and would like to use S3 on their PCs. Sadly, the advice I offer on that post isn’t going to work because of the mysterious step 5 and the required regkey.