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Shut off, Won't Restart... The Troubles Cease to End.

By Eedarf
Apr 16, 2006
  1. Running a 400w Powersupply to an A8N32 - SLI Motherboard with a GeForce 7900 Video Card. A few days ago, I was running Oblivion and out of nowhere it crashed kinda akward. The screen froze and the part of the sound that was playing, continually repeated. (Clip of a clip, I guess is how to explain it. ) I wasn't up for redoing everything I'd just done, so I'd quit. Yesterday it did it again... Today I wasn't playing Oblivion. It just shut down and refused to restart.

    I'm running windows XP 64 bit Pro, so my Motherboard does not have the proper driver. Something I, ironically, intended to fix tomorrow by installing the 32 bit Pro. It sounds to me, in my limited experience and knowledge that I've somehow, be it related to my current hardware nightmare or not, burned out my Powersupply. Nothing looks to be damaged as far as burn marks. Opinions anyone?
     
  2. ICUB4UCME

    ICUB4UCME TS Rookie

    well, i could see a cheap 400w power supply easily being outstripped by an athlon64 and a high end vid card like that. a cheap one is most likely rated for 400w when its screaming for mercy and realistically should be called a 300w unit. since you didn't specify what brand of PSU i'm assuming you don't know and OEMs like to use cheap stuff whenever possible.

    i had a cheap PSU go out on me once with almost no sign of failure aside from the obvious refusal to power on. i swapped it out and everything was back to normal. after i took the blown PSU apart i saw almost every trace and solder joint on the circutboard was one big glob melted together. pretty brutal really
     
  3. Eedarf

    Eedarf TS Rookie Topic Starter Posts: 26

    So what's the recommended PSU, for the hip kids now-a-days?
     
  4. ICUB4UCME

    ICUB4UCME TS Rookie

    well, there are many brands that are of good quality and hold high reputation. brands like antec, sparkle, and enermax are always good choices. if you do a google search for "power supply roundup" or "power supply review" you will find many sites that have compared dozens of power supplies side by side and you can decide for yourself exactly what it is that you need.
     
  5. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

  6. kirock

    kirock TS Rookie Posts: 1,221

    PSU dead that's affirmative. I blew up my generic crappy 450W with my Athlon64 3500 and only a 6600GT! The 64 series CPU pulls 100+Watts alone from the 12V rail. With a 7900 and a 64CPU she would have been lucky to get through a single round of HL2! (the game I was playing when, bam, shmmmmooooooke) happened.

    Cheers.
     
  7. Eedarf

    Eedarf TS Rookie Topic Starter Posts: 26

    So where's the science in deciding the proper power supply? Is it just guessing? It can't be...
     
  8. ICUB4UCME

    ICUB4UCME TS Rookie

  9. kirock

    kirock TS Rookie Posts: 1,221

    The last post is an excellent suggestion, may I add "science" to your decision.

    1) 1st most important is the overall Wattage. whatever the above link calculates for you add at least 30% to that for head room.
    2.1) nothing is 100% effecient and even the world's best supplies can only go to 80-85%. This is calculated as PowerOut/PowerIn. PowerOut=Rated Wattage, Pin can be calculated from the Line Voltage and the Amp draw X0.707 (this is an AC to DC (RMS) correction factor). Example of Pin= 110VX7AX0.707= 544.39 Watts. Now if the unit is a 400W output, then Eff=(400/545)X100=73.4%.
    Why is this important? The LESS effecient the unit is the more HEAT it produces, and this it not good for itself, nor the case temperature.
    2.2) Most PSU are rated at the peak output, something they can sustain for a minute or so at maximum. So in the above example the 400W unit is really only rated 80% of that for continuous safe power out. So that would be approx(worse case) 320Watts!!!!!1 This is a huge and very significant difference over the rated 400Watts that the manufacturer would have you believe. NOTE: What you calculate from Extreme site is the continuous pwer required to run system at max load.
    3) The 12Volt rail supplies the fans, motors and CPU. Athlon 64 and P4 CPU's draw at least 100W from the 12V rail. you guest it, each the outputs (rails) have their own max Wattage. Example: 12VX22A= 264W. That's for all stuff needing 12V (fans, motors (HDD, DVD, CD) and the power hungry CPU) Take 100W away just for the CPU. This only leaves 164W to run the rest.
    POINT IS: Look for a PSU with lots of amps on the 12V output.
    4) 2 fans, low noise, nice cabling solution. Length, removable? This list is mostly esthetics, but the 2 fans do keep the PSU cooler and thus increases it's life and stabilty. Stable voltage on a hard working PC is CRITICAL, unless you like random reboots, BSODs and freezes.
    5) In closing: A PSU running at it's limit will overheat, fluctuate in voltage output and this will result in BSODs, reboots, freezes and other nasties like component damage. If you just installed an FX-60 would you like a $40 PSU to kill your $1000+ CPU?

    Cheers.
     
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