Power shuts down

My power supply shuts down immediately on startup. Disconnecting the 4 pin ATX12V aux connector gets the power supply running, but of course I cannot boot the CPU. This behavior in intermittent. The CPU will boot and run for weeks at a time, then stop. After a period of time disconnected, the cpu will boot and run normally again. There is no excessive heat or warning beeps. The supply is 450 Watts and the system has a single SATA 1GB drive and DVD RW, 4GB ram one case 80mm fan and regular CPU fan looks to use about 330 watts max. ASUS m3n78-em - AMD Phenom 9750 Is it power supply or mother board?
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  1. Best answer
    You may have a failing power supply. I recommend a good brand such as corsair, pc power and cooling, seasonic, antec, ocz or enermax. Lots of folks try to get by with some lightweight no name branded ps after spending a small fortune on their pc. Changing to a better brand is a good investment in the long run.
  2. Thanks, I am getting a new PS to swap in and see if it solves the problem.
  3. Quote:
    you need to have a lot of power for that equipment you have

    A web PS calculator estimates 246 Watts for the setup I described. That leaves 200 watts to spare even if the estimate is off a bit.

    The mobo is rated for
    140 watts/onboard ATI HD5200/Phenonm X4,
    CPU fan, 2 case fans (10w), 120 and 80mm,
    1 SATA HDD (30W),
    1 Sata DVR/RW (30W),
    USB (20W)
    2X2048MB DDR2 (30W).


    either wey a correct functioning 450 Watt supply should be ok, I think.
    Am i missing something? I am assuming the 140W mobo includes the CPU.
  4. Quote:
    try unplug all the fan and see it work better to test PSU

    Yes I removed everything but the mobo and still shuts down. If I remove the 4 Pin aux connector fromthe mobo, the PS runs ok.

    I also tried removing the memory and got the power supply running, but obviously memory error.
  5. Quote:
    it doesnt include the cpu, you need to have some watts for every core to run. times it by four.

    +125 W according to the spec. so 395 watts on a 450W PS, closer than I want, but should run.

    Is it typical behavior for the PS to simply shut down immediately if short on power?
  6. so you would recommend upgrading to a minimum 500 watt PS.

    thanks for the input.
  7. Power Up replaced the power supply last weekend and after 3 days it remains up and running with a new 450 Watt ps. SO far so good.
  8. Best answer selected by tonydr58.
  9. New 450 watt power supply resolved the issue. The original was an "Extreme" and was replaced by a "Power Up". The new supply had better DC output ratings at 5 and 12 volts, but I feel like the original was defective. While it worked for about 6 weeks, it finally failed and could no longer operate a under load.

    Thanks for everyone's input.
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