[blizzard]

Pretty simple question...I know that I always put my computer to sleep at night, that it goes silent virtually instantly, and wakes up again the next morning almost as instantly. So what goes on behind the scenes? I'm guessing the hard drive spins down, the fan powers off, but the RAM is still supplied with a trickle of power...is that about it?

[anti-sleep]

That's it exactly.

[derekn]

The USB still has a bit of power too I think, you can wake up by hitting a key on there. Other than that, yeah everything is powered down. Not sure on actual wattage ratings but it's likely not much more than what a system uses when it's actually shut off.

[Joe Cool]

I remember Jobs saying it was cheaper to sleep your computer than to power a normal light bulb all the time.

[D'Espice]

There are three different states of sleep: Sleep, deep sleep and hibernation (also called S1, S3 and STD, it's an ACPI specification).

Sleep (S1):
The processor, harddrive, mainboard and memory are still supplied with power, however the video card, network and other external devices like USB printers or scanners aren't. USB itself is supplied with 5V Standby power which means you can wake up your computer by hitting a key on your keyboard.

Deep sleep (S3, Suspend to RAM):
Everything except for the memory is powered down, the content of the microprocessor's cache is written into memory and and the computer practically powers off. USB is still supplied with 5V Standby so you can wake up your computer by hitting a key on your keyboard.

Hibernation (STD, Suspend to Disk):
The content of the RAM is written onto a file on the harddrive and the computer powers down. You can unplug it and carry it around, whatever you want. If you turn it on again, the content will be written back into the memory and it'll be right where you put it to very very deep sleep


Macs use deep sleep and - in some cases - sleep, Windows computers use deep sleep, in some cases sleep and Windows Millenium Edition, Windows 2000 and Windows XP are also able to hibernate.

[wapangy]

Originally posted by D'Espice:
Macs use deep sleep and - in some cases - sleep, Windows computers use deep sleep, in some cases sleep and Windows Millenium Edition, Windows 2000 and Windows XP are also able to hibernate.

Windows hibernation stinks though, it takes as long to wake up as it does to start up.

[blizzard]

Cool...thanks for the answers guys!

[coolmacdude]

Originally posted by Joe Cool:
I remember Jobs saying it was cheaper to sleep your computer than to power a normal light bulb all the time.

I would certainly think so, because a fully active G4 processor uses less than a light bulb.

[D'Espice]

Originally posted by wapangy:
Windows hibernation stinks though, it takes as long to wake up as it does to start up.

That's b***s***, my Windows 2000 machine takes almost 2 minutes to boot up but only 43 seconds to wake up form hibernation. And may I remind you that this includes all open aps.
My Windows XP takes around 50 seconds to boot and around 30 seconds to wake up from hibernation.

I don't know a single PC that takes as loong to wake up as it does to start up.

[derekn]

Is the hibernation in Windows what Virtual PC uses? Can't recall the name but you can just shut down the VPC app and save the desktop or something. You just relaunch the app and it's right back to where it was, no Windows bootup necessary.