I'm so confused....

[fuzzybabybunny]

Now, correct me if I'm wrong, but I was under the impression that when a computer's on standby, it:

1. shuts down hard drives
2. leaves things like the PSU and fans on

I just put my computer in standby, and EVERYTHING shut off, including PSU.

Now I go to turn it back on and everything pops back in a second, so it was in standby...

Did they change how standby works or something?

 

[Lord Evermore]

There are multiple levels of standby. The best one is hibernation, or S4, which shuts down everything and saves the OS state to a file on the hard drive; the computer is effectively turned off entirely in this mode, just like if you hit the ATX power switch, and can be unplugged if you want and not lose data. Booting up is much faster than if you'd shut the system down via the OS, because it doesn't have to process all the bootup files and start any applications, they're already loaded directly into memory in their previous state along with any open files. S4 is implemented in the operating system, the BIOS doesn't have anything to do with it really.

S3 is "suspend to RAM", which stores the OS state in the RAM, and shuts down all other devices and components leaves just a trickle of charge to keep the RAM refreshing. This allows an almost instant boot-up, because the all that has to be done is spin up the fans and hard drive, but the OS state doesn't have to be read off the hard drive. All data is lost if you unplug the power or switch off the PSU. The BIOS has to support this. This is most likely the mode that your computer is using when it goes into standby.

S1 is most likely the state you are thinking ought to happen. It leaves pretty much everything running, but shuts off the high-draw devices like hard drives, and the CPU just stops processing instructions. Many mainboards come with S1 as their default power management setting for when the OS instructs to go into standby or sleep mode. It uses much more power than S3 mode, but doesn't really start up much faster since you still have to wait for the hard drive to spin up.

The OS is not aware of whether the system will be using S1 or S3 when it is instructed to go into sleep mode, as that is controlled by the BIOS. (S2 is rarely implemented.)

http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface

 

[fuzzybabybunny]

Cool. I just remembered that all my other computers did S1, and I was confused when it did S3. Hibernation takes a while, and the computer definitely shut down more or less immediately, which is why I thought something screwed up during my "entering standby" phase.

I HAD thought about the possibility that somehow my computer was now suspending to RAM, but two things I wasn't sure of:

1. I've never seen this done before. I wasn't even sure if it existed.
2. My PSU isn't on... at least the fan wasn't turning anymore BECAUSE the fan is connected to one of the PSU's external wires, not internally to the PSU. Long story short, it's hooked up like this because the stock fan is too loud, so I took it out and replaced it with an externally controlled and powered fan.

Since this fan shuts off during standby, and I'm thinking the stock PSU fan would not, is it unsafe to go into standby? It was in standby for a good four hours and the PSU still seems fine.

 

[Lord Evermore]

I replaced a PSU fan like that once too.

The PSU fan does shut down when it goes into S3 mode. S3 is only providing I think 5V power to the board, and it's extremely low current draw to power the memory, so the passive cooling of the PSU heatsinks is enough.

 

[Navid]

Even if you completely shut down your computer, as long as you leave the PSU plugged to the wall power outlet and do not flip the switch at the back off, the power supply still provides a 5V supply (called standby) to the motherboard.

Although no fan spins (not even a stock PSU fan), there are some components on the motherboard that are on and allow it to turn on the PC by pressing the power switch which is connected to the motherboard (and not the PSU). Some motherboards have an LED on them that is on in this phase also.

I have a Kill-A-Watt unit, which can be used to measure the power usage. My PSU consumes about 5W when shut down. This is very small power and does not require a fan for cooling.

 

[Lord Evermore]

That's ATX "soft-off" mode. S3 mode uses a lot more power than that because it has to power the RAM, while soft-off is only powering a monitor circuit.

 

[Navid]

Originally posted by: Lord Evermore
That's ATX "soft-off" mode. S3 mode uses a lot more power than that because it has to power the RAM, while soft-off is only powering a monitor circuit.

Don't forget that the power consumed in RAM is a function of how fast the data in RAM changes. While in standby, the content of RAM does not change at all. So, its power consumption would be negligible.

Anyway, I think we agree that the power supply fan does not need to spin when in standby mode.

 

[Lovehandles]

I remember when I was studying for my A+ certification the author mentioned power levels like suspend and standby are meant for laptops only. Which makes perfect sense when you think about that fact that laptops (sometimes) operate solely on battery power and desktop units do not. In all the years I've been using my desktop PC - I've never felt the need to use those power levels. The only thing that I've changed is to have the moniotor automatically power down after 20 minutes of non use.

 

[Nothinman]

I remember when I was studying for my A+ certification the author mentioned power levels like suspend and standby are meant for laptops only. Which makes perfect sense when you think about that fact that laptops (sometimes) operate solely on battery power and desktop units do not. In all the years I've been using my desktop PC - I've never felt the need to use those power levels. The only thing that I've changed is to have the moniotor automatically power down after 20 minutes of non use.

If you're the one paying the power bill and you have more than one machine it can make a noticable difference if you put your machines into standby or not. Personally I can't do this because I always have torrents and crap going so I can't let the box sleep, but if the box is doing nothing at all I don't see a reason to leave it up.

 

[Lovehandles]

There are benefits (IMO) of leaving a box running regardless of whether you use bit torrent or not. Everytime you start/ shut down the computer, you are exacting more wear and tear on the system components. Heat exands and contracts the electrical components inside and over the long-haul - that places more wear & tear on the components. That is why I leave mine running 24/7 unless I know I'll ge gone for several days. Furthermore, the power it consumes is nothing compared to the power consumption of some CRT monitors which is why I use power management to have the monitor go off after 20 minutes.

 

[Nothinman]

There are benefits (IMO) of leaving a box running regardless of whether you use bit torrent or not. Everytime you start/ shut down the computer, you are exacting more wear and tear on the system components. Heat exands and contracts the electrical components inside and over the long-haul - that places more wear & tear on the components.

While true to an extent, most people don't care. By the time the components die from use you'll most likely have long replaced them.

 

[jzinckgra]

So if my computer is uploading data to my website every 10 min, can I use any of those stanby modes that were mentioned? I usually leave the puter on also, but turn the monitor off.

 

[Nothinman]

So if my computer is uploading data to my website every 10 min, can I use any of those stanby modes that were mentioned? I usually leave the puter on also, but turn the monitor off.

Not really, while the box is in standby the only thing actually doing anything is the memory so any scheduled tasks will be missed.

 

[Lord Evermore]

Originally posted by: Navid
Don't forget that the power consumed in RAM is a function of how fast the data in RAM changes. While in standby, the content of RAM does not change at all. So, its power consumption would be negligible.

DRAM must be continuously refreshed, even if nothing is changed. It may be slightly less than if data were being changed as well but it's still a lot more than soft-off mode which is zero power. Of course the energy required for DRAM is definitely negligible compared to a fully-active system, or even just S1 mode.

 

[Lord Evermore]

Originally posted by: Nothinman

So if my computer is uploading data to my website every 10 min, can I use any of those stanby modes that were mentioned? I usually leave the puter on also, but turn the monitor off.

Not really, while the box is in standby the only thing actually doing anything is the memory so any scheduled tasks will be missed.

I think in S1 mode it might be possible for a timer to wake the machine up to run a task.

Or you could solder up an external timer connected to a PCI interface chip and card and set the power management to wake up on activity from PCI devices.

Having it turning on and off every 10 minutes might actually be enough to cause earlier death, though it still isn't enough of an issue I think that anybody could statistically prove that caused the failure.

Let the hard drive and monitor go into standby mode after 1 minute of no activity and you'll save at least some power.

 

[Navid]

Originally posted by: Lord Evermore

Originally posted by: Navid
Don't forget that the power consumed in RAM is a function of how fast the data in RAM changes. While in standby, the content of RAM does not change at all. So, its power consumption would be negligible.

DRAM must be continuously refreshed, even if nothing is changed. It may be slightly less than if data were being changed as well but it's still a lot more than soft-off mode which is zero power. Of course the energy required for DRAM is definitely negligible compared to a fully-active system, or even just S1 mode.

Most of the power is consumed when data changes in the DRAM also. The power is consumed for charging and discharging of the load capacitors due to the change of content. Some power is also required for the clock circuitry. That is why I said the power consumption would be negligible and not 0.

Think of a flip-flop. All of its internal nodes need to charge and discharge as well as its clock input if its content changes. Usually, the largest capacitor is on the output node though (parasitic capacitance of the metal tracks). But, if the same data is applied to it and it is only clocked, the only thing that changes is its clock input. That of course consumes power. But, negligible!

I am glad that it is unanimous that the PSU fan does not need to spin in standby mode.

 

[Nothinman]

I think in S1 mode it might be possible for a timer to wake the machine up to run a task.

Yea, you could have the BIOS wake the box up every 10 minutes, but at that point you might as well just leave the box on all of the time.