[WIP] ATX PSU Maximum Combined 12v Ratings

Discussion in 'General Hardware' started by Makalu, Nov 30, 2006.

  1. neoblasted

    neoblasted Member

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    GPU:
    BFG Nvidia 8800GTS 640m
    nice! thanks DUDE!
     
  2. joe_star

    joe_star Member

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    GPU:
    eVga 8800GTS 320MB Superclock
    Just thought I'd mention that the silverstone strider st56f version 3 that I got claims to have a maximum 40Amps on the 12v rails. Anyone can verify this?
     
  3. kwak

    kwak Ancient Guru

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    do you have a pic of the label on the psu? im pretty shure that you can trust silverstone to put the right amperages on their labels.
     
  4. Makalu

    Makalu Ancient Guru

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    yeah that's right...new version of the ST56F has 40A combined...thanks for the heads-up on that...I'll check the other Striders for version changes and update the list to reflect that,
     

  5. SniperDaws

    SniperDaws Banned

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    The 3.3/5v rail is responsible for the motherboard, memory, PCI cards, AGP card and so on. The 12v rail is responsible for the HDDs, DVD, CD-ROM, fans, etc.

    is the above info correct? if so why is everyone hungry for more power on the 12volt rail?
     
  6. Makalu

    Makalu Ancient Guru

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    yeah that's basically correct...except the motherboard and the AGP slot use some 12v and the drives use a bit of 5v too (drive motors use 12v and the rest of the circuits use 5v). It's the increase in CPU and GPU power consumption in recent years that required an increase in 12v capability...and also the transition away from using the 3.3v and 5v rails to help supply power to the CPU and GPU.
     
  7. SniperDaws

    SniperDaws Banned

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    GPU:
    XFX7600GTXXX Zalman Vf900
    so am i right in thinking that graphics cards that use extra power like a molex or 6pin are using power from the 12volt rail?


    Oh and thanks for the reply :)
     
  8. kwak

    kwak Ancient Guru

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    yes, the external power connectors on a graphics card only use +12v.
     
  9. Makalu

    Makalu Ancient Guru

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    The 6800 Ultra AGP card uses about 4 amps of 5 volt current delivered thru the external molex connector but I'm not aware of any other cards that use anything except the 12 volt source. Most AGP cards with an external connector get all their power thru the slot in 2D mode and the extra 3D consumption is provided by the molex 12v. PCI-E connectors of course only supply 12 volt power.
     
  10. Bushi123

    Bushi123 New Member

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  11. Makalu

    Makalu Ancient Guru

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    yeah it'll be more than enough for the system...and thanks for the spec info on that one I'll add it now :)

    It's the ZM600-HP's little brother so I would expect it to be a stable, quiet and cool PSU...not aware of any cons. I like the heatpipe assisted cooling.
     
    Last edited: Jun 12, 2007
  12. Bushi123

    Bushi123 New Member

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    Thanks, but unfortunatly I won't be able to get it cheap.
    Can you tell me if the Enermax Noisetaker EG425P-VE will be enough for the system in my previous post?
     
  13. Mulsiphix

    Mulsiphix Maha Guru

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    GPU:
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    I don't think that will be enough because of the GTS alone. That fact your OC the GTS I really doubt it will be powerful enough. I recommend a 500W to 550W for that setup.
     
  14. Bushi123

    Bushi123 New Member

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    But the EG425P-VE has a 29A on the +12V.
    Nvidia recommands a min 26A PSU, and on the BFG's box it says:
    "A 425W PCI Express-compliant system power supply with
    a combined 12V current rating of 28A or more*
    * Minimum system power requirement based on a typical PC configured
    with an Intel® Core™2 Extreme X6800 processor"
     
  15. Makalu

    Makalu Ancient Guru

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    well the Noisetaker is a step (or two) down in quality from the Zalman but it has plenty of juice for your system. The E6420 isn't going to draw more than about 6 amps (@12v) and the OCed 8800GTS 320mb will peak at about 9A@12v. So that's only 15 amps and the unit is rated at 29 amps combined which leaves plenty of room for the other 12v consumers (drives and fans...figure roughly 2A for each drive and .25-.33A for each fan) and still some overhead for efficiency and longevity.

    The Enermax Liberty 400's are usually priced about the same as the Noisetaker 420 and is a better and newer design with stabler voltages and a flatter efficiency curve than the Noisetaker series though. And a slightly stronger 12v output.
     

  16. Mulsiphix

    Mulsiphix Maha Guru

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    My apologies. I thought the GTS required at least 425W to power up. With everything else that needs power I figured a 500W would be about right. I need to remember its more about the amps than anything else when considering a PSU.
     
  17. Atrokkus

    Atrokkus Member

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    GPU:
    HIS ATI Radeon x1950 Pro 512MB AGP
    Please add this one to the rating: Huntkey LW-6400H
    Can't figure out how to calculate the 12v amperage on this one...

    I guess it should be about 30A, no?

    And this one as well
     
    Last edited: Jun 29, 2007
  18. Makalu

    Makalu Ancient Guru

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    well I could add the model names but the combined 12v rating would just be NG for Not Given like most of the other Coba/Huntkey units since I can't find the info either. Look on the label and see if it at least gives a combined 3.3v+5v rating and then we can make some assumptions about the lowest amount that the 12v rails must be capable of. Honestly, I would guess that the max combined is somewhere in the neighborhood of 18-20 amps for both of those units.
     
  19. Atrokkus

    Atrokkus Member

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    GPU:
    HIS ATI Radeon x1950 Pro 512MB AGP
    Ok, here's the exact copy of what is provided on the label (of the 400W one):

    DC Output: +5V=35A (RED), +12V=15A (YELLOW), +3.3V=26A (ORANGE), PG (GRAY)
    -5V=0.5A (WHITE), -12V=0.8A (BLUE), +5Vsb=2.0A (PURPLE)
    RATING OUTPUT WATTS 400W, +5V, +3.3V:240W,+5V +3.3V&+12V:380W

    Isn't the total output 380W then? which makes it a 31A PSU, right?
     
  20. Makalu

    Makalu Ancient Guru

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    well the 400W LW-6400 on their website is a dual rail version 2.0 unit and even though your unit might have the same model number it's an older version like 1.1 or so. Yours is single 12v rail and has the old -5v rail which was phased out some years ago. The maximum 12v rating of your unit is just as it says there...15 amps.
     

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