How many watts does my PC draw?

By Vidosoli
Dec 12, 2012
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  1. I'm currently going to buy a new and strong Video card, this video card tho require 250 W in order to be run correctly. Can someone tell me how I can find outh ow many Watts my pc uses??
  2. Blkfx1

    Blkfx1 TS Guru Posts: 954   +185

    You can use a tool like this. You enter your hardware and it will calculate a wattage for you.
    What PSU do you currently have?
  3. slh28

    slh28 TechSpot Paladin Posts: 1,926   +170

    Those PSU calculators usually give you very inflated numbers, try looking up some reviews which have a similar setup to yours. Biggest power draws are the CPU and GPU, the other components (RAM, hard drives, fans, etc.) don't really use that much power. Overclocking will also significantly increase your power usage.

    But yeah, it would be useful if you list your current setup and the GPU which you're thinking of getting.
    Blkfx1 likes this.
  4. Blkfx1

    Blkfx1 TS Guru Posts: 954   +185

    Hmm, I didn't know that. I've never used one personally but, I did assume they were some what accurate.
  5. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 6,004   +144

    Purchase a multimeter, or look up each of your components specifications from the manufacturers website. They will give you max TDP, but you will want to have that covered +20% anyway.
  6. slh28

    slh28 TechSpot Paladin Posts: 1,926   +170

    When I type in my setup I get 952W from that Newegg calculator, and I assume that's for everything at stock. I have a 40% OC on the CPU and 20% OC on both the GPUs and have never had issues with a good quality 850W unit. It's definitely good to have some headroom but don't want too much overkill.
  7. red1776

    red1776 Omnipotent Ruler of the Universe Posts: 6,004   +144

    ....and they laugh at my 2.2kW triple PSU setup ROFL
    This is without the water pumps, fans, SSD, lights, etc

    ...anyway you want a 20% headroom with your PSU for heat and efficiency reasons.

  8. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,920   +388

    They recommend 464W for my setup. I'm running an Enermax Noisetaker II 485W PSU. I also have a Kill-a-Watt meter, and when I had an 8800GTS 320 I don't think I ever saw it pulling more than 270W from the wall while gaming. I now have a Radeon 5830, which may pull less than my 8800GTS 320 did.
  9. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,401   +237

    PSU ratings are usually for when the PSU is at 20-25C for most brands (which is a useless temperature to rate a PSU at imho - who has a PSU running at 20C at load?). They can de-rate at higher temperatures quite significantly. Also as they age they de-rate as the components degrade so all this headroom is a very good thing.

    So while you see 270W draw, your PSU capacity at reasonable temp could be a fair bit less than 485W...
  10. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 4,393   +136

    They told me I needed 320w, which isn't a bad estimate actually.
    I'm running an Antec Earthwatts 380w, and I do have a kill-a-watt meter but I've yet to try it out on my computer.
  11. SNGX1275

    SNGX1275 TS Forces Special Posts: 12,920   +388

    I know. But my point was that the PSU calculator wants a 464W PSU for my system, but in reality my system pulls 270W from the wall under load. Taking that load reading from the wall removes the necessity to deal with inefficiencies in converting AC to DC, so unless my PSU degraded in its capacity to around 50% of its rated, I wouldn't have any problems.

    The 464W is a VAST overestimation for my particular setup. I'm not saying this will be true across the board, just throwing some support behind slh28's comment.
  12. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 4,393   +136

    I support that comment too, if you're unsure you should ask here (before you buy not after).
  13. Darth Shiv

    Darth Shiv TS Evangelist Posts: 1,401   +237

    Maybe the calculator is factoring in some padding... worst case scenarios for HDDs, video cards with overclocks etc...

    Also PSU efficiency is usually best well inside the max capacity (closer to 50-70% of max). I wonder if that is also factored into the calculator?
  14. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 4,393   +136

    Much more than necessary IMO.
  15. Row1

    Row1 TS Maniac Posts: 416   +12

    Use the Kill-A-Watt to get a real measure. Once you have that number, then look online at review articles to see if someone has evaluated how much power that specific card can require.
    I agree that you need a power supply that has at lest 20% more power than your computer will draw.
  16. hahahanoobs

    hahahanoobs TS Maniac Posts: 1,403   +238

    If you have to ask, then you're not sitting on any kind of computer powerhouse, so take the recommended wattage required for the video card you want to buy, and add 100w.
  17. Spacelord999

    Spacelord999 TS Rookie

    this is power supply calculator.

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