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PSU or Mobo?


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Current PSU: neo480W

Current Mobo: Asus A8N SLI Deluxe

On order: HX620W PSU


Here's my symptoms:

For most of the year my PC has exhibited this behaviour. If the PC is powering on/off fine, all is well each time. If I unplug the PSU from my wall outlet, and then plug it back in, the PC will not boot. A green light on the mobo comes on, but nothing powers up. In the past, if i hit the button to turn the PC on a million times it would eventually come on, and everything would be fine again until the next time I unplugged from the wall.


Well, I was rerouting some AC connections on the weekend, and now my PC will not boot at all.. not even after hitting the button a 'million' times.


So I figure it's the PSU (see my system specs below) and I've ordered the HX620. I then came across a thread here that shows you how to short out the green/black on the PSU, hook up a fan in the case and see what happens (http://www.houseofhelp.com/forums/showthread.php?t=63991). To my surprise, my fans fired right up. So does this mean my PSU is actually fine, and that my mobo is the problem? Or could it still mean my PSU is the problem, in that it's overworked with all of my components and hence not powering up my system?


I appreciate your thoughts / suggestions. Wondering if this means I should be mobo shopping now...

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I'd lean towards an over-driven power supply whose over-current protection circuits are finally kicking in. The specs for that 8800gts call for 26 amps on the +12 volt rail (the biggest surge in current draw usually happens at boot up). The EVGA link (scroll for the +12volt amperage spec):




The neo480 spec sheet and data page:






The neo480 is a +12volt dual independent rail design with +15 amps on one rail and +18 amps on the other rail (they can't borrow amps from each other). As electronic components age, they usually start drawing a bit more amperage and it looks like the system has just gone over the limit of what that supply can output without the current limiting heat protection circuits kicking in. Component ageing is one of the reasons to select a supply for any system with about 15 to 25% more capacity than initially needed (this is usually refered to as power supply "headroom"). The Hx620 will give you massive headroom (single +12volt rail design at 50amps) and should solve the problem nicely.


ps: since fans don't draw much power, they're unlikely to trip the over-current protection.

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Thanks so much for your response.


Looking forward to the Corsair, and hopefully my problems resolved.


One last question.. does it mean my neo480 is still a good functioning PSU that I could reuse in another sytem that doesn't require as much power? Or does it mean it's ready for the scrap heap?


And on the 620hx.. if i went to 2 x 8800 GTS (not planning, but might in the future), will I still be ok in your opinion?


Thanks again

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Garvin is correct. Your system may be drawing too much power from your current PSU upon startup, or the board may be going out of spec. If you get the 620HX and still have the same issues then I would replace the board. The 620HX will power 2x 8800 cards with no problems.
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