When I shut down my computer (XP SP3) the window says
Stand by Shut down Restart
I know what the last two are but have never quite figured out what “Stand By” is. Is it the same as “Hibernate” (which I also never understood)? My computer is a laptop- if I’m in Stand By mode, can I close the cover and carry it around? Or is Stand By just for when you go off and leave it for long periods like overnight? What is the power consumption during Stand By? Please 'splain it to me. Thank you.
standby can do one of two things depending on how your system is configured:
S1 standby: the disk drives, display adapter, and other peripherals are shut down. The power supply remains fully on, the CPU is awake but sent little more than HALT instructions, and system memory is fully powered. Your system is basically still “On” but some things are turned off to save a little power.
S3 standby: the disk drive, display adapter, other peripherals, and the CPU are turned off. The power supply is off apart from the +5 volt standby line, which works to keep the memory controller and system memory active. your system is basically “Off” but just enough is kept awake to let it start back up almost instantly.
Hibernate: the entire contents of system memory are written to a special file on the hard drive (hiberfil.sys,) the boot loader is modified, and the system is turned completely off. When you restart, the bootloader points to the hibernation file, reloads the system state into system memory, and it boots up exactly where it was when you left it instead of starting from scratch.
ETA: there are more “S” states than that (like S0, S2, etc.) but S1 and S3 are nearly always the only ones implemented as standby.
How do I know which “states” I have implemented? Is this something I configure myself?
Also, can I carry the computer around when it is in Stand By or Hibernate?
desktop or laptop?
…
Reading OPs is for losers.
This is something I’ve always wondered: Is it any more 'risky" to carry around a laptop in standby as opposed to hibernate? Of course the power will eventual drain, but I mean in terms of possibly harming the hard drive, or maybe losing data. I do it all the time, and never have had a problem, but I’ve always wonder about it.
My tendency is to avoid hibernation, because I sense that after coming out of hibernation the computer runs slower. Is this just a misconception?
Awesome - I was going to answer this question before it was solicited. Thanks for soliciting. 
Standby and Hibernation don’t hash the PW like the OS does when it’s fully shut down. Windows is also (especially XP and previous versions) vulnerable to silly shizzle like rainbow tables. It’s worth noting that even with whole-disk encryption, this is an effective attack vector. If you’re letting the machine get touched by someone else’s hands, shut the whole thing down.
The machine will, indeed, run slower for a while coming out of hibernation, since
the active session’s data is stored to memory; you’re chewing up a big chunk of the available memory (and page file). It should, however, stabilize after it gets its feet back on the ground (that might take several minutes).
I understood most of what you said except “rainbow tables” and “attack vector.” Are you saying it’s safe mechanically and physically to carry the laptop around in Stand By mode, but security is vulnerable in that state?
Correct. The hazard with carrying around a running computer is that spinning things (hard drive, optical drive) have a tendency to go off balance and destroy themselves. These components are shut off in standby, so you can go ahead and move your computer around.
Which standby state your computer uses should be of little or no value to you. All you need to know is that the disk drive is off, so you can carry it around treat it as if it was off.
Standby: You can treat the laptop as if it were off. It boots up faster because your last session is still completely in memory and all of the programs/documents that you were working on will still be open. The only drawback is that it uses a little bit of battery power to keep the memory state alive, so this won’t work indefinitely.
Hibernate: You can treat the laptop as if it were off. It boots up more slowly than standby, but faster than if it were off. Your last session will come up as you left it and all programs/documents that you were working on will still be open. Hibernate does not use power from the battery since it writes your memory to the hard drive. Your laptop may stay in Hibernate indefinitely since it uses no battery power.
Very clear now. Thanks, y’all.