Game Design, Programming and running a one-man games business…

Updating my pc power-usage measurements

Ages ago I blogged about how I used a kill-a-watt gadget to measure my PC power usage. I was recently motivated to check on the usage of my newer PC. Read the old post, and you’ll see it was a Dual Core 6600 Intel PC with 2 gig RAM and vista. The bootup power usage was 160 watts.

I have since upgraded, and am typing this on an Intel 8 core i7 chip, running at 2.80GHZ. There is now 8 gigs of RAM running on 64 bit windows 7, rather than vista. The PC has an ATI Radeon HD 5700 video card. The measurement was abse unit only, no monitors.

Do you think the 8 core 5700 combo uses more or less power?




The readings are as follows:

  • On boot-up, after windows has just loaded and no apps are running 133 Watts (less than the old PC)
  • After a while to let everythibng settle down, and stuff liek steam had all been turned off to minimsie network traffic. (I couldnt get the hard disk to totally shut down though)  107 Watts (less than the old PC)
  • Running Gratuitous Space Battles with an average battle in a window at 1680 x1050 res, all options set to maximum 143 Watts.
  • Running Gratuitous Space Battles fullscreen at 1920 x1200 res, all options set to maximum 141 Watts
  • Re-compiling the game, using Visual studio, maxxing out all 8 cores, and no doubt some fair amount of disk-thrashing 192 Watts.

What surprises me is that GSB, as a mostly single-threaded single-core game, uses 73% of the power of a maxxed out CPU-thrash. Could all that power really be going on fans and hard drive gubbins? and maybe powering the other chips on the motherboard, the video card etc.

In any event, 132 watts for a PC that is theoretically doing sod all is in some ways a LOT, and other ways nothing. The UK price for power is 11.5p per unit which is 1 killowatt hour. That means my PC, when on, is costing me (132/1000) * 11.5 = 1.51 pence per hour, or at 10 hours a day 330 days a year, roughly £50, or $75. Peanuts really.

But given that my electricity usage is £39 a month, that rates it as 10% of my power usage. That’s without the router, printer,scanner or two monitors. Obviously this is only electricity, not heating.

In comparison, assume I boil a kettle 6 times a day, it uses 2000 watts for 2 minutes each time. So thats roughly £16 a year, or 3.4% of my power usage.

I suspect the biggest power usage is the PC and laptops, and everything else just makes up a multitude of tiny power draws around the house. Bah.

7 thoughts on Updating my pc power-usage measurements

  1. Of course in summer that energy is just wasted. But in the winter when you have heating on it may not be. If your room is thermostatically controlled, or if you even just wait until you are cold before turning on the heating then it’s likely that energy came straight off your heating bill….

    I’m not suggesting it is all that efficient, however it is likely heating the one place where you are are most likely to be sitting. I consider that for perhaps 1/4 of the year in the UK the energy used by my PC and related equipment is essentially *free* as every watt output by my PC is a watt my heater doesn’t need to use to keep the temperate constant.

  2. some of that energy is wasted as noise or virbation too. Plus, it’s likely heating up a part of the house that isn’t ideal as a heating source.

  3. Get an SSD and you will rejoice. The difference between a harddrive and a SSD is like NOTHING you have ever seen. And you can then also happily live with 2GB of RAM, because you simply will not notice any swapping.

  4. Noise and vibration end up as heat too… but yeah, not trying to say it makes a huge difference, but its got to make some :)

  5. “What surprises me is that GSB, as a mostly single-threaded single-core game, uses 73% of the power of a maxxed out CPU-thrash. Could all that power really be going on fans and hard drive gubbins?”

    Uhm… on the 3D Card (although maybe looking 2D)?
    There is some serious power loss on those graphic monsters!

    If you want to get those max-numbers try furmark (maxing out 3d Graphics)
    and Prime Benchmark (maxing out CPU).

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