How can I find out how many watts my PC pulls from the wall?

By Atham
Oct 1, 2011
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  1. Hello,

    I would like to find out how much watts my PC uses. I do not have any measuring devices for wattage, so is there still a way?

    Thanks
  2. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,419   +281

    To get anything other than a guess you'll need a device like the Kill-a-Watt. I'm not sure the availability in your country but with a company name of p3international it at least sounds like you could get it.

    You could also do it with an amp probe. The difficulty here is that you'd have to separate the hot wire and the neutral one, so that may be difficult or impossible (not to mention unsafe if you cut the insulation into the wire).
  3. Atham

    Atham TechSpot Enthusiast Topic Starter Posts: 517

    I will be going to this place where old PCs are stored. Probably they could have one of these measuring devices.

    You mentioned something about a guess. How could I do that?
  4. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,419   +281

    You could get a guess by looking at the TDP of your processor and the TDP of your video card. Then maybe add 5W for the motherboard, a watt or two for USB peripherals (unless they are 2.5" hds), 12-15W spinup for hds (maybe 5-7W under use, probably a couple less for idle). And a few watts for any other PCI or PCIe cards. Then take that number and add 20-25% to that and thats probably a rough guess of what the max is you will pull from the wall. I have you add the 20-25% because PSUs are not 100% efficient, so they'll draw more out of the wall than your components are asking just because some of the power gets lost in the conversion from AC to DC.

    Now most of the time your processor and GPU aren't pulling anywhere near what their max TDP is. So you could probably google around and see similar systems' idle power with (ideally) your GPU and CPU. It probably won't happen ideally though and you'll have to do some deduction to figure out how much each pull on idle.
  5. Atham

    Atham TechSpot Enthusiast Topic Starter Posts: 517

    My max TDP is 65 watts apparently.
    I have an IGP - so I don't know how many watts that is.
    I use a mouse, a keyboard, and an USB WiFi connector.
    One HDD.
    One IDE optical drive
    I have a Case embedded PSU that is 400 watt.

    So let's see that will be:

    (65 watts + 5 watts + 7 watt + 7 watts + 10 watts) *1.3 = 122 Watts

    Could that be right? If I add a 9800GT it will be 258 watts if GPU is on full. A Seasonic X-660 should be sufficient.
  6. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,419   +281

    Yes, that will be plenty. Your calculations are probably pretty close, when I hooked my computer up to a kill-a-watt I was fairly surprised at how low the actual power consumption was.
  7. Atham

    Atham TechSpot Enthusiast Topic Starter Posts: 517

    Really. What was the certification?

    Now I need to convince my dad that me buying the X 660 is a good thing and not wasted money if I will add the 9800GT 1GB and later a HD 6950.
  8. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,419   +281

    I had the same system I do now in my specs but with an 8800GTS 320, and during heavy gaming I was ~250W from the wall.
  9. hellokitty[hk]

    hellokitty[hk] I'm a TechSpot Evangelist Posts: 4,318   +117

    A seasonic x-660 is a waste of money though isn't it?
    You can get a sufficient power supply for cheaper.
  10. Atham

    Atham TechSpot Enthusiast Topic Starter Posts: 517

    I will be getting a hd 6950 2 GB toxic, flashing it to a 6970.
  11. Atham

    Atham TechSpot Enthusiast Topic Starter Posts: 517

    You say it is not worth the cash? Why do you think so>
    I might be getting a new CPU and Mobo next year. Maybe I will consider CF or use a 9800GT 1GB as PhysX.

    What would you recommend using this setup:
    CPU AMD Athlon II x2 240 2.8GHz Regor
    Motherboard MSI 785GM-E51
    Memory Kingston 2 x 2GB DDR3 Dual Channel @ 1066MHz
    Graphics Card HD 6950 2GB Toxic running as a 6970
    Hard Drive WDC WD10EARS-003BB1 ATA Device 1TB
    Sound Card Integrated
    Power Supply x
    Case Eurocase Middle Tower 5425
    CPU cooling Stock cooler
    GPU cooling N/A
    OS Windows Ultimate 64 Bit
    Monitor ASUS VH242 24" 1920 x 1080

    Would the SeaSonic M12II 520 Bronze be good enough for the system above?

    And for this setup:
    CPU AMD Bulldozer series
    Motherboard GA-990FXA-UD3/UD5/UD7
    Memory Corsair Vengeance 2 x 4GB DDR3 Dual Channel @ 1600MHz
    Graphics Card HD 6950 2GB Toxic running as a 6970 with possible 9800GT 1GB as a PhysX card
    Hard Drive WDC WD10EARS-003BB1 ATA Device 1TB
    Sound Card Integrated
    Power Supply x
    Case Coolermaster HAF 932 or HAF X
    CPU cooling Corsair H70
    GPU cooling N/A
    OS Windows Ultimate 64 Bit
    Monitor ASUS VH242 24" 1920 x 1080
     
  12. hellokitty[hk]

    hellokitty[hk] I'm a TechSpot Evangelist Posts: 4,318   +117



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