best way to save energy with a pc ? (hibernate/standby etc)

Discussion in 'Desktop & Laptop Computers Forum' started by throwit, Mar 21, 2006.

  1. throwit

    throwit
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    hi

    in the MCE forum there is a discussion about electricity usage costs, and i think i was in the wrong place to ask this question, as they need to keep their pcs operating or something

    apparently a pc in standby still uses about 25 watts, now this isn't the end of the world (although it also kind of is) but i was wondering what the deal is...does a pc have to draw anything at all ?

    lets say you want quick access to your pc but also want to be able to use less energy at other times, standby it is said uses 25 watts approximately, but what about hibernate - in power options it says that hibernation stores all open apps (assuming you have free system space to do so) and shuts down

    it should be theoretically possible that either the pc will use no juice from this point (unless the power on switch requires active power supply to read the 'press') so there is no cost with a hibernated pc, or that once hibernated, a pc can be physically unplugged and plugged back in before de-hibernating

    i'm pretty sure that more than once i've hibernated the pc when i've had to move it or whatnot, and then managed to plug in and de-hibernate

    can anyone tell me what's the deal ? is my hibernated pc using juice ? or not ?

    while i'm here, i don't suppose anyone knows of any circuit breakers (i.e. stops a surge, and acts as a switch) with kettle connectors (is that whats called in line ?), please ?...as i can use these (if they exist) as a compact "total kill" switch and of course there's an element of added safety

    cheers, matt :)
     
  2. clockworks

    clockworks
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    A hibernated PC should use the same amount of electricity as one that's been fully shut down.
    In both cases, there is still a "pilot" voltage on the motherboard, which supplies the power switch, and the wake on mouse, keyboard, LAN, etc. monitoring circuits. A laptop will also monitor the lid switch.

    As you said, hibernation dumps RAM to the HDD, meaning boot times are reduced. Apart from that, it's the same as being totally shut down.

    In sleep mode, the RAM is continually being refreshed, hence the relatively high power consumption.
     
  3. Pootle

    Pootle
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    Yes it is, nearly all PC's when "switched off" still power part of the motherboard, and other things, but the power used depends on the PC and varies widely. This applies whether shut down or hibernated. In both these cases you can unplug / switch off at the mains and then it will really be using no power.

    Suspend also varies a lot. Recent laptops and tablets can draw only a few watts on suspend, older machines are not nearly as efficient on suspend. A Stylistic tablet PC I tested could run all weekend on suspend, and use only a few % battery, and took only a few seconds to be fully operational again.My desktop PC draws about 120 watts (just the PC, not the monitor) running, "switched off" it draws 5 watts.

    If you want to find out what is really happening, buy a mains power meter from Maplins for around £10
     
  4. throwit

    throwit
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    thankyou clockworks and Pootle

    so hibernate is a good temporary as well as long term "off" solution ? but can anyone help me find an in-line kettle (iec ?) connector circuit breaker ? (would quite like one of these for my pc and pj and amp that all run off the ups)


    i run my pc and pj off a ups, so i guess i should probably put that meter between the wall socket and that - the ups itself may be caning a fair proportion of my use...does anyone know if there are kettle connector power meters ?

    they might look something like this...
     

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  5. Pootle

    Pootle
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    You might be lucky, but even if you find one, it may be expensive. You could turn the cheapo Maplin 13amp one into a kettle type by spending a few extra quid on some kettle type plugs and sockets and a bit of cable, plus you could still use it as a 13amp device to check out other kit around the house - this can be quite revealing :)
    Please post back here with what you find - it would be useful to know:smashin:
     
  6. spuddler

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    Hi,just connect meter to mains.Then do measurements with it connected to UPS,then direct into PC(My UPS & PC have Kettle input connections).Have PC idling for both tests.Also test with projector on etc etc(I have PC & Projector powered by UPS).

    Cheers BOB
     
  7. Nick_UK

    Nick_UK
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    Buy the Maplin power meter and make up an adaptor cable for it. Your UPS is probably taking about 5-10 Watts to keep its batteries topped up.
     

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