Is there any way to measure PCI Power Usage?

Discussion in 'Mac Pro' started by minifridge1138, Jun 9, 2013.

  1. minifridge1138 macrumors 6502a

    Joined:
    Jun 26, 2010
    #1
    Hello Everyone,

    I'm wondering if there is any way to measure the amount of power being used by the PCI rows on the LB.

    I' thinking of adding a GT 640 for an additional 65W. I know it isn't a powerful card, but it's a cheap way to get 10X the number of cuda cores I have now (GT 120 has 32 cuda cores). I don't need to power a display with it.

    I already have:
    Apple 5870 = 75W (6 pin) + 75W (6pin) + 38W (PCI) = 188W (AMD Spec)
    Apple GT 120 = 50W (PCI) = NVidia Spec

    The GT 640 would only use 65W from the PCI lane, so i'm good on paper. I'd just like to see what I'm actually using.

    thanks!!!
     
  2. Thessman macrumors regular

    Joined:
    Dec 8, 2005
    Location:
    GR
    #2
    1 istat
    2 Hardware Monitor
     
  3. ThisIsNotMe macrumors 68000

    Joined:
    Aug 11, 2008
    #3
    1) Buy Card
    2) Install Card
    3) Test Card
    4a) Profit
    4b) Return Card For Full Refund
     
  4. Inconsequential macrumors 68000

    Joined:
    Sep 12, 2007
    #4
    What are you worried about?

    You've got 75W from the slot irrespective of what else is plugged in to other slots.

    istat menus shows power draw (version 3 NOT 4). Only accurate to +/- 10% I'd imagine.
     
  5. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #5
    Why would the accuracy be lower than "near exactly" or "spot on"?
     
  6. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #6
    v4 does that too. I use this one. Accuracy seems pretty good, it shows 2 digits after comma. Reads amps, but you can quickly convert them using e.g. this: http://www.rapidtables.com/calc/electric/Amp_to_Watt_Calculator.htm
     
  7. Inconsequential macrumors 68000

    Joined:
    Sep 12, 2007
    #7
    Has he put power draw back then? It's one of the reasons why I went back to 3.

    Also, just because it goes down to 2 decimal places does not mean it is an accurate value, just that it has a high resolution.
     
  8. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #8
    Yes, power draw reading works in 4.05 I have.

    I understand that iStat reads values from hardware sensors, correct? If so, it should be as accurate as sensors are.
     
  9. Inconsequential macrumors 68000

    Joined:
    Sep 12, 2007
    #9
    The sensors arnt going to be accurate to much more than 5%, or even if we are lucky 1%.
     
  10. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland

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