How much more can my PSU take?

Discussion in 'AMD x86 CPUs and chipsets' started by Chiamh, Aug 17, 2012.

  1. Chiamh

    Chiamh Member

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    Hi all,

    I recently upgraded from an Athlon II x2 250 to a Phenom II x4 955. Turns out my motherboard doesnt officially support the CPU but it works anyway (yeah, i know, shouldve checked before i upgraded but oh well).

    I have done some googling and the consensus is that as long as i don't overclock the motherboard should hold up ok. What do you guys think – am i risking blowing the mosfets on my motherboard or am i right if i dont OC?

    The other question i have is how much room to move do i have with video cards? Is the HD7770 likely the most powerful card my PSU can support with my build or should i stick with the HD7750? Currently using a HD4830..

    Full system specs:
    Phenom II x4 955 (125w TDP)
    Gigabyte GA-MA78GM-S2H (version 1.0)
    Sapphire 512mb HD4830
    4x1gb DDR2 800 RAM
    Antec NSK2480 case with Antec Earthwatts 350w PSU (came with case).

    Other things that draw power..
    2x HDD's
    1x DVDRW
    1x PCI Wifi card
    plus usb but im sure they dont draw much..

    Appreciate the feedback, thanks
     
  2. sandeep

    sandeep Member

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    Hey mate, very likely you are overloading that PSU. It is very risky as it could blow up one day and catch fire. It is dangerous.
     
  3. Creekin

    Creekin (Taking a Break)

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    waitwot!?! :wired:
    get a bigger psu first!
    i wouldnt feel right running that rig on a 550w
    no way i would do it on that
    somethings going to let the magic blue smoke out thats for sure! :Paranoid:
     
  4. Exige

    Exige (Banned or Deleted)

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    Get a power meter and see what kind of current you are drawing.
     
  5. OP
    OP
    Chiamh

    Chiamh Member

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    eek really!

    It hasnt missed a beat so far since the upgrade, although i've only really been gaming with diablo 3 on it. Damn, i really dont want to have to buy another PSU either ;/
     
  6. NNNG

    NNNG Member

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    If it can run a 4830 then a 7770 should be fine. I wouldn't bother the the 7750.

    But it's a good idea to get a better power supply to be safe.
     
  7. Creekin

    Creekin (Taking a Break)

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  8. OP
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    Chiamh

    Chiamh Member

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    hm just checked using http://extreme.outervision.com/PSUEngine - not sure how accurate this is..

    with the hd4830 it recommends a 337w PSU, using a hd7770 its 339w. I'll definately trim down to 1hdd though to save what i can on power.
     
  9. OP
    OP
    Chiamh

    Chiamh Member

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    better to be safe than sorry i guess ;/ I just double checked too and its an Antec Earthwatts 380w PSU not 350.. but yeah still probably overworked a bit.. I am more worried about the motherboard dying with the 125w CPU to be honest..
     
    Last edited: Aug 18, 2012
  10. AEKaBeer

    AEKaBeer Member

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    Undervolt the cpu to 1.25v (some go lower) it will save you ~30-50w.
     
  11. Exige

    Exige (Banned or Deleted)

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    That's 125w of thermal dissipation, it's not an accurate representation of load current. That's also when it's runnning at 100%.

    More of a worry is what your individual ampage draw is, on your 12V lines. A 500w psu can be worse than a 380w PSU if the 380w has more allocated to
    12V.
     
  12. OP
    OP
    Chiamh

    Chiamh Member

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    So what figures would be adequate for my current system? I'll crack open my case and look now
     
  13. mAJORD

    mAJORD Member

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    It's been fine because it's simply not overloaded.

    The PSU can do 336W on the 12V rail (s), which is likely "just enough", but gives you ~ 0 headroom under a full load.

    Due to the nature of consumers over-specing power supplies in their machines, even good supplies really aren't designed to last long loaded to the max. Sure they'll pass or exceed 100% loading to smash through a hardware reviews, but wouldn't expect a long service life if you use it like this every day (unlike say, an industrial power supply which is designed to be loaded to its rating 24/7) Not just talking about total failure either, as components age its ability to deliver 100% rating will also drop off.

    Of course most people don't 100% load their machine every day anyway, but always assume you will, I guess. (maybe you'll get into folding or something)

    So.. given the cheapness of even a quality PSU these days, you'd probably use a good 450-500W on that machine. something with at least 400W combined on the 12V rails.

    A small OC at stock voltage won't hurt either, but if you want to stick the Voltage stick up your new video card, and/or a new mobo at a later date, you'd want to move to an even higher power supply for more headroom.
     
    Last edited: Aug 18, 2012
  14. OP
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    Chiamh

    Chiamh Member

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    I had a feeling id be pushing it upgrading from the athlon ii x2 to the phenom ii x4. Ah well.. PSU upgrade time i guess ;/
     
  15. xok

    xok Member

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    What?

    PSU are vastly overrated for what they run, you'll be fine. It's an Antec unit (I believe it might be a seasonic under there, but at the very minimum it's a very good low wattage unit).

    I ran an i3, 6850, 2 sticks of ram, a sound card (titanium HD), 3 hard drives, a fan controller and an SSD plus a DVD drive in my NSK3480 for about 8 months, and never had a single issue. You'd be pushing a bit more with that Phenom2, but honestly, your rig probably draws a lot less.

    If you have a look at some benchmarks around the place, i've seen pretty low and conservative readings of what quad core pc's and decent GFX cards pull from the wall.

    http://www.bit-tech.net/hardware/cpus/2011/07/13/amd-phenom-ii-x4-980-black-edition/7

    In this, the max draw (with an mATX board, atx board may add extra 20w) was 197w, for what is likely a barebones system. Remember that this is from the wall, and the PSU is 80plus, so it's likely dissipating a percentage (up to 20% as heat) Add in your GFX and your HDDs etc, and then you'll have a rough figure, which is hopefully around what the PSU is rated at. Now, decent power supplies can actually outperform their specs, and as long as it's not shit (it isn't), it'll be fine.

    A psu upgrade would be smart if you've got the money around, but I wouldn't stress running your system on it. It's a good PSU, a bit noisy with the stock fan though...
     
  16. TaroT

    TaroT Member

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    i disagree and so do the 12 dead antec 350 psu's i have.

    I do not rate those psu's at all and would never recommend using them even with a low-end system.

    The ones i had were cronic for overheating and the rails were all over the place even on lighter loads.

    If you had a 350 or have one now that runs fine then my guess is they changed suppliers and i,ll go and kick these old one a few more times for fun but i would run a multimeter on the thing then occt the hell out of it and see if the system and psu are stable.

    Also throw one of those elcheapo wattage meters (you can get the from coles now :) ) on at the same time and see what nominal and full system draw is then decide.
    but if it was my computer i would use it as a paperweight.
     
  17. OP
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    Chiamh

    Chiamh Member

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    Thanks, this was the more like the impression i had. It is an antec unit, as opposed to a seasonic so i figured i'd be fine.
     
  18. c_hegge

    c_hegge Member

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    I'm assuming you're referring to the Antec Smartpower 350? If so, I agree. We sold lots of them at work a few years ago, and guess what? EVERY SINGLE ONE died, long before the PC had to be retired, and several took the motherboards out with them.

    The problem was that Antec and CWT (The company that built the smartpowers for Antec) used fuhjyyu branded capacitors - one of the worst brands available, so after a few years the caps went bad and the ripple went through the roof.

    Between all my dead PSUs and the trouble I had with my Antec 1200 case falling apart and the fans failing, It will be a long time before I buy another antec product.
     
  19. OP
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    Chiamh

    Chiamh Member

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