Is the wattage meter faulty or what?

Discussion in 'Power Supplies' started by M76, Aug 16, 2015.

  1. M76

    M76 [H]ardForum Junkie

    Messages:
    9,002
    Joined:
    Jun 12, 2012
    I connected a meter to the rig in my sig, and I was shocked out of my mind.

    It showed 450 W at idle, and 1600 W at load. Is that possible or is the meter faulty? I mean it can't be, since I only have a 1000 W PSU, and I have no stability issues or sudden reboots, so the reading isn't right, right?
     
  2. elavanis

    elavanis n00b

    Messages:
    37
    Joined:
    Feb 1, 2008
    It doesn't sound to far off to me. I know when i put my old video card (amd 6870) in the power usage tripled while sitting at the desktop. Having 2 in crossfire may make it 6x. Also the important thing to note here is you are measuring the power from the wall and the power supply is measuring the power it is able to put out. Not sure if you included your monitor in the power usage or just the computer.

    I haven't put a power meter on my cpu lately but the setup is a i7-2600, amd 7870, 2 ssd and a mechanical hd. I know the 3 lcd took about 100w each to run and if i remember the computer was taking about 100 at idle with the old video card. It has a corsair cx 600 power supply for efficiency reference. If i remember I'll post my power usage after i get back from church this afternoon.
     
  3. M76

    M76 [H]ardForum Junkie

    Messages:
    9,002
    Joined:
    Jun 12, 2012
    I know that there is a difference between what the psu can put out and what it draws. But it's supposed to be a 80+ PSU, so it should only draw 1200W at maximum capacity. The display is included but it only uses around 30W. So that leaves at least 350W unaccounted for, assuming that the PSU is at 100% load, which I highly doubt.

    Edit: I tested the same system, before I installed the 2nd 290x, and the CPU was at default, so no OC, and it showed 600W under load. There is no way the OC and the second GPU draws another 1000W.
     
    Last edited: Aug 16, 2015
  4. Streiw

    Streiw Bad Santa Gifter 2016

    Messages:
    505
    Joined:
    May 9, 2015
    It's a faulty meter. No way in hell would a 1kW PSU be stable at 1.6kW.
     
  5. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    And the power supply is?

    But in general, no.

    Matching up to the link software doesn't mean much as neither the power meter you are using nor the software is accurate or reliable ;)
     
  6. mnewxcv

    mnewxcv [H]ardness Supreme

    Messages:
    6,306
    Joined:
    Mar 4, 2007
    you need to plug the computer cord directly into the meter (directly into the wall). not the power strip with monitor, speakers, etc. do just the tower, and tell us what you find.
     
  7. Tsumi

    Tsumi [H]ardForum Junkie

    Messages:
    12,982
    Joined:
    Mar 18, 2010
    [H]OCP has said that the Kill-a-Watt meters and other cheap power meters do not play well with APFC PSUs.
     
  8. M76

    M76 [H]ardForum Junkie

    Messages:
    9,002
    Joined:
    Jun 12, 2012
    Lepa Maxgold G1000-MB

    I guess it could be caused by the APFC, since I think when I did the last measurement I still had my old psu, which was many years old, and nowhere near the efficiency of current ones. But it was APFC too, Chieftec CFT-750-14CS
     
  9. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    Very easily. A broken clock is right twice a day. You are using a piece of hardware that has very low accuracy and software that pulls from a very cheap hardware (if it was actually an accurate and precise piece of hardware it would cost a lot more) as well. Corsair will, of course, argue that it is very accurate (as will people who don't know what they are dealing with) but that monitor is not nearly as accurate as a real power meter nor is it calibrated. I have tested a number of the software/hardware monitors out there and as yet none have been accurate and some were neither accurate nor precise. The way they work varies and a number of implementations don't actually read values at all under certain circumstances but use a lookup table to give a predicted value. As for your kill-a-watt the pictures are floating around of lots of incorrect readings that I and others have collected. In a couple weeks you'll get to see even more numbers.
     
    Last edited: Aug 16, 2015
  10. Zepher

    Zepher [H]ipster Replacement

    Messages:
    16,716
    Joined:
    Sep 29, 2001
    What about one of these?
    [​IMG]

    What about the software for the UPS, how accurate/inaccurate is that?

    This is what the software says for my system. I was listening to music on iTunes and reading this thread when I took the snapshot.
    Everything on my desk is plugged into the UPS, 4790K machine in my sig, LG 34" monitor, M-Audio BX5 speakers and BX 10" subwoofer, 7 port powered USB hub,
    2TB USB3 External drive, WD 8 port gigabit switch, HP DV7 laptop (powered off but plugged in), 36" fluorescent light, desk thermometer/clock.
    [​IMG]

    And this is the UPS on the 3770K setup, just the tower, 2 cable modems, router, and switch are powered on,
    [​IMG]
     
    Last edited: Aug 16, 2015
  11. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    Unfortunately, I have not reviewed that unit so I don't know for sure if it has any funky harmonics, etc. However, I know the platform and it is not that inefficient at full load. So, if just the power supply is plugged in it is the meter.
     
  12. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    Very old (by tech standards don't tell BillR) and unless it has been serviced and calibrated it is not nearly as accurate as newer test gear not least of which because the read out is actually stepped instead of continuous as it appears. It also has the issue of only being as accurate as it is going to be at a fixed voltage IIRC. Also, if you hang around old audio stuff the people that used them used to complain about diodes on them blowing a lot so longevity and functionality along with accuracy and precision if nothing has been done to it would likely be suspect. It's like old variacs. Sure they were built better than the new cheap ones (not necessarily better than the new good quality ones), but if you did no service on them like the brushes they are about as useful as a boat anchor (and likely heavy enough to be one).
     
  13. Zepher

    Zepher [H]ipster Replacement

    Messages:
    16,716
    Joined:
    Sep 29, 2001
    Hey Paul, I updated my post above asking about the UPS software, not sure if you noticed it.
    And that old Sencore was given to me, I don't even know if I still have it, may have tossed it when I redid my room a few years ago.
     
  14. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    I would have to have the UPS, the software, and disassemble the UPS to know how it was being done. That said, accurate power meters cost more than most consumer UPS's so......
     
  15. primetime

    primetime [H]ardness Supreme

    Messages:
    5,559
    Joined:
    Aug 17, 2005
    maybe you can post a link to the meter just for educational reasons
     
  16. Zepher

    Zepher [H]ipster Replacement

    Messages:
    16,716
    Joined:
    Sep 29, 2001
  17. Paul_Johnson

    Paul_Johnson [H] Admin Staff Member

    Messages:
    15,476
    Joined:
    Aug 29, 2004
    ? There are tons. You can spend $1,000 or you can spend $10,000+. Is it a basic single channel power meter, or a more capable analyzer, or does it have a built AC source? If it has the AC source what capacity, etc. If you want one then HP/Agilent/Keysight, Chroma, Yokogawa, Fluke, Manta, etc make quality ones you'll just have to poke around until you fine what you want then request a quote. Or you can look at the second hand market (but it's always somewhat dicey) and you'll find them from nothing on ebay to $2000 to $30000. You can also pick up any number of Taiwanese or Chinese "brands" but even the good ones there will still be more than a UPS. The ones we have in the family shop are Chroma 6620(x) and there is a Yokogawa.
     
    Last edited: Aug 18, 2015