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Power Consumption of a Typical PC While Gaming 211

cliffski writes "How much does your PC really draw in terms of power when idle, when in sleep, and when playing a demanding game? I don't trust everything the manufacturers of hardware say, so I thought I'd get myself a watt measuring device and run a few tests on some of the gear I leave on all the time, and the gear I go to the trouble of turning off. The Linksys router drew 8 watts, the monitor drew a fairly noticeable 30-31, but what surprised me was how little power the base unit drew, even when playing Company of Heroes. Also, the variance of power draw for Vista seemed minimal, regardless of what you got the machine to do."
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Power Consumption of a Typical PC While Gaming

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  • by CambodiaSam ( 1153015 ) on Wednesday June 25, 2008 @02:33PM (#23938493)
    What about the thermal impact? I live in a hot climate, so leaving a PC on seems to have a big impact on the temperature of the room. Sure, I might use a couple hundred Watts to run the gear, but what about the electricity required for the A/C to cool the room back down?

    Hey, when it's 100 deg F outside, I notice the difference.
    • Re: (Score:2, Funny)

      by AkaKaryuu ( 1062882 )
      I've had a _very_ notible temperature change in my old apartment when both my friend and I ran our Macbook Pros. Them's hot laptops. Makes you wonder what kind of damage they do to the little friend in your pants.
      • by argent ( 18001 )

        If you can use your Macbook Pro on your lap you've got tougher *legs* than I do, let alone anything you keep between them.

    • Re: (Score:2, Interesting)

      So does your computer, powersupplies get less efficeint the warmer the room is. So while your useing only 200 watts, at 70 degrees, at 85 degrees, it's probably past 250.

      • by mollymoo ( 202721 ) on Wednesday June 25, 2008 @05:59PM (#23941629) Journal

        So does your computer, powersupplies get less efficeint the warmer the room is. So while your useing only 200 watts, at 70 degrees, at 85 degrees, it's probably past 250.

        Resistance does increase with temperature and a thermally controlled fan will spin faster and draw more current. But enough for a 25% rise in consumption from a 15 degree (in unspecified units, I guess you mean Fahrenheit) temperature rise? That's seems like a hell of a lot for a fairly modest rise in temperature.

        For an 80% efficient power supply, an increase of 25% overall consumption is more than double the power loss. The reality is very complex, but we can pick out a few relevant numbers to get a feel for the magnitudes involved. Empirical testing would be easier than an analysis, but here's some food for thought:

        For copper, the resistance rises by about 0.4% per degree Celsius rise. Your roughly 7 Celsius rise would increase it by a whopping 2.8%. You'll have melted the insulation well before even a 50% rise in the resistance of your copper wire.

        If you look inside a power supply, you'll see a big fat heatsink. Attached to that are rectifiers and switches - diodes and FETs. That's where a big proportion of your power supply's inefficiency comes from. Looking at the first power FET datasheet I have to hand (for a Fairchild HUF75337P3), the on resistance increases by something like 1% per degree Celsius rise. For diodes because the forward voltage drop actually decreases with increasing junction temperature - they get more efficient. For an International Rectifier 12CWQ03FN it looks to be about 0.2% lower per degree Celsius rise.

        The YS-Tech 80mm fans in this box next to me consume 0.84W at full speed. That's a slow fan though, I wouldn't be surprised if more typical ones used 2-3W at full speed.

        Hardly a complete analysis, but just can't see where you're getting this additional 50W from. I think you're out by an order of magnitude.

    • Back in the day, I had my server (an AMD Athlon64 2800+), my workstation (2x AMD Athlon MP 2400+), my wifes computer (P-IV 2.6GHz HT) and a huge Colour Laser printer (Ricoh Aficio CL2000) in a 10 square metre office. All the machines were pretty much on all the time.

      We never ever needed to turn on the heating in that room. Even when it was -15C outside. In the summer you couldn't stay there for more than half an hour if you dared to close the door. The machines stayed stable though....

      We now cut down seriously on the amount of machines we have in our office. (Let's say that getting rid of the MP was already an immense change...)

      • by mr_mischief ( 456295 ) on Wednesday June 25, 2008 @02:59PM (#23938915) Journal

        I used to work for an ISP which was contacted by the natural gas utility company about canceling service. The gas company decided it wasn't doing us as the customer nor them as the seller any good to keep billing us just for the pipe, as we used about 2 units of gas in the five years at our location. With four offices, a lobby, the call center, and the NOC, we were self-sustaining for heat. Cooling, on the other hand, cost us dearly.

      • Re: (Score:3, Interesting)

        by Shivetya ( 243324 )

        I moved my office downstairs. Simply put, the lower floor is always cooler in summer and the heat difference in winter isn't justification to have a system upstairs.

        As such, the upstairs is left at 82F during the day while not in use, goes down to 78 starting that nearly an hour before expected time to turn in.

      • Re: (Score:3, Informative)

        by sm62704 ( 957197 )

        Laser printers are power hogs by the very way they work. They're space heaters! If you have a laser printer running, it most likely consumes more power than all your other hardware combined, and certainly puts out more heat.

        The way a laser printer works is that the laser beam puts an electrostatic charge wherever it lands - which wouold be where you want the paper to be black.

        The charge on the paper attracts the toner, which is black plastic ground into fine powder. A heater in the unit, at 1800 degrees f,

        • by Khyber ( 864651 )

          "the toner, which is black plastic ground into fine powder."

          you forgot the iron and carbon black. Also, it's not really a plastic, it's more like a wax. You can use a block of it at room temperature just like a crayon.

        • the real problem isn't the fact that they have a corona wire, though, the problem is that most of them don't do enough power saving. The HPLJ5550n (terrible PITA, but beautiful output, very expensive to operate as well I'm afraid) will shut itself down so far it takes as long to start up as from a full cold boot. My HPLJ2100 (much older, B&W only) cycles its fan somewhat frequently because it generates too much heat even in standby.
      • Back in the day, I had my server (an AMD Athlon64 2800+)

        To me, "back in the day" implies more than 3 years ago.

    • Re: (Score:2, Interesting)

      by wolf12886 ( 1206182 )
      Depending on where you live, that could work the other way as well, ie, offsetting your heating bill.

      My tower doesn't produce much heat, but when I'm gaming with my 360, I swear its like having a space heater on, if you've never felt the air coming out of the exhaust fans, its something like putting your hand at the mouth of a hair dryer.
      • I miss my old 360 in the winter :P
        The Falcon Elite I have now is a huge improvement in cooling, but no longer a space heater.

      • True, but your computer's a pretty expensive heat source, compared to gas or an electric heat pump.

        If you have resistive central heat in your house, it would be a wash. And, of course, if you keep it on the floor under your desk it is in a good position for space heating.

    • by antdude ( 79039 )

      Yep, same here. My upstair room can go up over 85 degrees(F) with a fan and central unit AC running! I have a bunch of electronics in my tiny room. I try to unplug stuff I don't use like TVs and printer. I also try to use AMD Cool'n'Quiet [] on my AMD systems. I also turn off machines that I don't use, but Linux/Debian box and wired network devices stay 24/7. Same for my old VCR (yes, still use one for recordings). :(

    • Re: (Score:3, Informative)

      by Macman408 ( 1308925 )

      Typical air conditioning can remove heat from your house with a 30-45% penalty; eg running a 100W appliance might cost another 35W in air conditioning. Incidentally, at least for air conditioning planning, I've seen a human listed as producing about 600 BTUs per hour, or 175 Watts. So your room might be warming up as much from you using the computer as it is from the computer itself.

      Also, some people seem surprised that their computer has a 450W power supply even though it is only drawing 150 Watts. This

      • If you buy a computer from Apple or Dell, the power supply needs to have enough capacity to handle not only what you're getting, plus power for extra

        I don't know about Apple, but I can tell you that Dell, IBM, HP and probably most other big-name vendors tend to use the smallest possible power supply that can keep the machine running, with just enough headroom to outlast the warranty (power supplies get weaker with age). The same is often true of local shops.

        I've got an IBM P3 with a 100w power supply, from a decade ago when 250w was standard, and 300w was l33t. I've worked on countless P4 Dells where the power supply was either 150w or 220w. Just a

    • I've noticed this too.

      Assuming adiabatic conditions (Not typical, but can occur) and walls with a specific heat of zero (obviously bogus) in a 12 x 12 x 8 foot closed room, a system drawing 200 Watts will raise the temperature of the air by over 30 degrees F per hour (further assuming I didn't totally botch the math).

      Of course, even if you were adiabatic to begin with, raising the temperature is going to undo that (thankfully), meaning your computer just keeps things a few degrees warmer than if it we
  • I love kill-a-watt (Score:5, Interesting)

    by Bandman ( 86149 ) <`moc.liamg' `ta' `namdnab'> on Wednesday June 25, 2008 @02:36PM (#23938525) Homepage

    My wife is huge into low-energy tools, and she got us a kill-a-watt to play with.

    In my server racks, I've got the PDU equivalent of this [] from APC. They've helped me many times in load balancing the power draw across our circuits

    • by penguin_dance ( 536599 ) on Wednesday June 25, 2008 @02:46PM (#23938695)

      My wife is huge into low-energy tools, and she got us a kill-a-watt to play with.

      Hey pervert, keep your smutty bedroom toys to yourself! :P

    • by gEvil (beta) ( 945888 ) on Wednesday June 25, 2008 @02:50PM (#23938769)
      My wife is huge into low-energy tools

      Obviously. She married you.
    • ... wife ... huge ... tools ... play with.

      ... racks ... load ...

      Freud, call on line 2, Freud, call on line 2.
  • by gearloos ( 816828 ) on Wednesday June 25, 2008 @02:37PM (#23938551)
    Personally my I^2 R losses are always better if I'm kicking the box and screaming after a good wow gank.
  • I'm still using a 19" crt, which pulls a huge amount of power, but for the rest of the system (which is very old) it pulls about 325 watts when playing Warcraft3, unless my meter is calibrated wrong.

    For the antique buffs out there, it's an athlon xp with and old radeon 9xxx series, half a dozen optical and hard drives, and a dozen fans. add in the cold cathodes and fancy cooling crap that I thought was neat back in school, and 325 watts doesn't seem all that bad.
    • by 0racle ( 667029 )
      Athlons are antiques?
    • This is why I have a laptop. I got it as my severance for being fired for understanding that the boss' son-in-law is an idiot, and probably wouldn't otherwise have one yet, although I am soon preparing to purchase a quad-core laptop with non-quadro nvidia graphics (I am soliciting suggestions, and would like to get the best laptop I can get without getting excessive... 4GB RAM and 160+ GB only, please) :P My nw9440 requires substantial hacking for proper operation and I want something that's designed to the
  • Little information (Score:3, Interesting)

    by Kelz ( 611260 ) on Wednesday June 25, 2008 @02:46PM (#23938701)
    All he talked about with regards to the PC was the processor and video card. What power supply was he using? A super efficient one or a super stable one? How many peripherals were hooked in? Hard drives? Fans?
    • by cliffski ( 65094 ) on Wednesday June 25, 2008 @03:00PM (#23938931) Homepage

      Hi. Theres a single hard drive in there. a typical 'shipped with the box' PSU, no wireless card or anything fancy.
      The PC is from mesh Computers, about a year old.

  • Worth the cost (Score:4, Interesting)

    by wolf12886 ( 1206182 ) on Wednesday June 25, 2008 @02:51PM (#23938785)
    Where I live we pay $.08 per kilowatt hour, so running my computer 24/7 costs me (assuming 190 watts at idle) $11 a month, which is not nothing, but is certainly worth the convenience.

    Also, I doubt the leds on any of the devices mentioned account for nearly any of the measured current draw, 20ma at 5v is .1w, so you'd have to have to have a hell of alot of leds to make a noticeable difference in power usage. most of that current is probably being burned up in the wall wart, linear regulators or transmitters, if I had to guess.
    • by hurfy ( 735314 )

      lol, haven't gotten around to plugging the meter yet but i count 59 LED between my computer/hub/modem plus the 3 little blacklight bulbs :) Doesn't run them all the time and most of the fan lights are off or very low. Full power looks and sounds like a 747 on takeoff but not needed for cooling.

      New project is now to test out my vintage iron. Note to check max rating on kill-a-watt first before trying the mini-computer with the 5 digit BTU rating ;)

      I did find that my desktop uses almost the same power 'off' a

    • Where I live we pay $.08 per kilowatt hour, so running my computer 24/7 costs me (assuming 190 watts at idle) $11 a month,

      In Denmark (central Copenhagen) one kilowatt hour is priced at 0.44 USD (just reduced from 0.49 this month btw). So running a unit with a consumption of 190 watts for a day costs about 2.00 USD and approx 60.2 USD a month. Between 5 and 6 times as much as you pay.

      The price is higher than in Sweden (our neighbouring country) but lower than other countries in the European Union.

      My DELL XPS gaming rig certainly uses more than 190 watts when playing games. I would estimate at least 500 watts including the

      • n Denmark (central Copenhagen) one kilowatt hour is priced at 0.44 USD (just reduced from 0.49 this month btw)

        Yeah but you Danish get the majority of your power from wind and over renewables don't you? I'd rather pay the high price for that than the situation we have here in the UK now where we just pay a high price and destroy the environemnt

  • I have 4 monitors on my machine. 3 19" LCD's and 1 22" LCD. The PC itself is a Q6600 @ 3.1ghz and 2 HD3870's, also overclocked. The CPU and 2 GPUs are watercooled. There are also 4 hard drives and a sound card.

    I've think I've estimated the power draw at around 450w under full load (not including the monitors. 3 of them are turned off when I play games).

    Luckily I don't pay my electric bill.

  • been wondering about this also.
    mainly due to having only one 20A outlet, and the building is old enough I don't want to risk that much.
    looking to build a new system, I want to make a strong but low power-draw system (gonna use a 45nm intel chip). Looking at specs on various parts suppliers sites, I come across numbers like "total thermal dissipation", or things like the notes on Intel's ATOM board: "fully populated board with accessories uses 75W max"

    Where do I find out exactly how much wattage I need?
    A lo

    • by Amouth ( 879122 )

      kinda simple

      watts = amps * voltage

      if you are in the US normal AC is between 110-125v

      at 20 amps that outlet can provide 2,200-2,500 watts before the current load flips the breaker

      unless you have alot of computers all on the same circute you don't need to worrie about the draw on the outlet

      at home i have 2 computers 1 lcd monitor 1 crt monitor a laser printer and networking stuff.. constant draw is about 250 watts (at 124v that is 2 amps) when the printer fires up it draws 10 amps for a second but other than

      • unless you have alot of computers all on the same circute you don't need to worrie about the draw on the outlet
        And if you have more than one person in your home, you do need a lot of computers all on the same circuit for a multiplayer game because most mainstream PC games don't have an HTPC mode that lets players share a single large screen.
    • Unless you're playing 3d games, it might be easier to get a laptop instead of building your own. Don't bother with Atom, it's too underpowered for desktop use.

  • Accuracy (Score:5, Interesting)

    by Anonymous Coward on Wednesday June 25, 2008 @03:10PM (#23939091)

    I wonder how accurate those readings are. Cheap power meters often only produce correct values for purely resistive loads. Everything uses switching power supplies nowdays (they're very efficient compared to linear power supplies), and they draw current in peculiar ways (some have power factor correction which improves things). Does anyone have a Kill-a-Watt vs Oscilloscope accuracy comparison for different kinds of loads?

    • by dpilot ( 134227 )

      My kill-a-watt can also display the power factor. That doesn't say anything about how accurate it is, but it does say that it knows something about non-resistive loads. Incidentally, the switching supplies in the PCs I've measured have a power factor of about 67%.

      • Re: (Score:3, Insightful)

        by Trogre ( 513942 )

        My cheap power meter displays power factor, but not very accurately. It will tell me an AC fan has a power factor of 33% (correct) and an early-model switch-mode PSU has a power factor of 100% (wrong).

        After seeing the effects of several hundred inductive loads on an AC grid, I now only buy PSUs with Active Power Factor Correction. It costs less in the long run.

      • by afidel ( 530433 )
        Those are some seriously crappy PSU's! All good PSU's have power factor correction and will be in the 90% range. My datacenter averages 91% and that includes some big equipment that knows nothing about PFC.
    • Re:Accuracy (Score:4, Informative)

      by Quelain ( 256623 ) on Wednesday June 25, 2008 @06:31PM (#23942051)

      I don't think they are accurate at all on switch mode power supplies. I have one which is definitely wrong when measuring a PC PSU.

      I think they expect to see peak current at the peaks of AC voltage, but a switch mode PSU will take small bites of current which may or may not coincide with the voltage peaks.

  • by mariushm ( 1022195 ) on Wednesday June 25, 2008 @03:54PM (#23939771)

    Note that he uses Vista and he says his computer doesn't need more watts when playing games compared to normal usage.
    Maybe this is because Vista's 3D interface already taxes the video card and forces it to draw a lot of power?

    • Note that he uses Vista and he says his computer doesn't need more watts when playing games compared to normal usage. Maybe this is because Vista's 3D interface already taxes the video card and forces it to draw a lot of power?

      How often a day do you suppose Aero's DX9 effects are invoked in Vista? I am betting the load on the GPU is trivial when compared to 10 seconds of the gamer-geek's first person shooter.

      Power consumption and Vista's Aero interface [] [October 2006]

      "When the UI isn't doing anything,

    • by dave420 ( 699308 )
      It doesn't tax the 3D card a lot at all. Considering it's performing all the GUI in hardware, it's drawing a lot less power than if it was being rendered in software.
  • Most graphics card reviews these days test total system power consumption during idle and load. A sign of changing times I guess. Here's an example [] from Anandtech's review of the Radeon 4870. Pages 2-10 also have some very technical information about the architecture on ATI's new line of cards, for anyone who's interested.
  • by IYagami ( 136831 ) on Wednesday June 25, 2008 @05:50PM (#23941527)

    You should take a look at []

    This is the main information:
    Power Consumption in Games
    PS3: 185.9 Watt average
    XBox360: 176,54
    PC (see link for more information): 156,6
    Wii: 16.8

  • by Ihmhi ( 1206036 ) <> on Wednesday June 25, 2008 @10:37PM (#23944401)

    After you figure out your kWh usage for your respective devices, this kWh cost calculator [] is useful for finding out how much it costs to run it during a period of time.

    I leave my computer on all the time. I highballed its power usage at 200 watts to factor in the speakers, monitor, and computer itself (the monitor is not on all the time, but the computer is nowhere near 200 watts - so I just did a rough estimate.

    You would also want to find out much a kWh costs in your state [] to plug in the correct values. I set it up for $0.11 a kWh, also a big higher estimate.

    My father insisted that my computer was the reason the power bill was over $200 one month. It's nice to be able to tell him that it only costs about $15 a month to use. (:

  • If anyone's interested, here's some power consumption info for a PowerMac Quad G5 (4x2.5GHz, 2 HD, 4.5G RAM, GeForce 7800GT). And after this Monday I'll be able to test a PowerMac V8! Idle: 190W Play 1 Movie: 225W Bittorrent, 50 connections, 200KB/s down, 80KB/s up: 205W Games: Dunno, I don't game Encoding 4 videos simultaneously: 320W (max I've ever seen) Sleep: 28W And the Kill-A-Watt power meter is an RMS metering device so it should be fairly accurate regardless if the power supply is a switcher or no

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