Why It is so Difficult to Test Power Supplies

Over the past couple of years few markets in the IT industry have grown as rapidly as the power supply sector. Faster and more powerful CPUs, GPUs, and other components have led to a need for better and more powerful PSUs. A few years ago, most would have laughed at the thought of a desktop PC with a 700W or greater PSU, and yet such designs are becoming increasingly common. Companies are sprouting out of the ground like mushrooms and everybody wants a share of this fast evolving market.

With growing interest in power supplies it is natural that websites will take an interest in reviewing and testing them. However, power supplies are not as easy to test as many other components. For example, unlike a graphics card, CPU, or motherboard it is not enough to simply plug it in and run several of the latest 3D shooters.


Unfortunately, most published reviews on the internet are done in this manner. The DC outputs are quickly measured separately with a multimeter - or even worse the motherboard's BIOS. The rails seem to be stable, it runs the test system without difficulty, and it is relatively quiet; good enough for a Gold Award! These kinds of reviews do more harm than good to the actual users.

Because of the simple test rigs that are employed, the power supplies are not even close to being fully loaded and thus the DC outputs are generally without problem. It is also difficult or impossible to find flaws in this manner which would otherwise prevent people from buying a dangerous product. A certain PSU might run in system A just fine only to break down from an overload in system B and cause damage to the whole system. In addition to this type of problem, cheaper power supplies lack security features which should have been there for a reason.

The bottom line is, a normal PC is just not enough to fully load a high-end power supply, and therefore it cannot be properly tested and surely not approved by such a configuration.

Index AnandTech Power Supply Test Methodology
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  • Adul - Thursday, July 12, 2007 - link

    I'd love to see a power supply catch fire :). Maybe one of the cheaper ones will break enough for this.
  • CrystalBay - Thursday, July 12, 2007 - link

    I would also like to see a short video of substandard PSU's lighting up...

    I'm sure many enthusiasts have had Dram's start flaming or smoke. But I have never had a PSU actually catch flame out....
  • Martimus - Thursday, July 12, 2007 - link

    I had a Antec NeoPower PSU spew black smoke. It was not fun. Also fried my motherboard. It was less than 6 months old too, and I wasn't using it at anywhere near it's supposed capacity.
  • BladeVenom - Thursday, July 12, 2007 - link

    quote:

    The bottom line is, a normal PC is just not enough to fully load a high-end power supply, and therefore it cannot be properly tested and surely not approved by such a configuration.


    Then test power supplies that are in the range that most people actually need. Also test some budget ones. Let's see which ones are good for the money, and which ones are fire hazards.
  • xsilver - Thursday, July 12, 2007 - link

    what is meant is that the idea of having a psu is NOT to load it to 100% capacity.
    and the problem being that it is very difficult to get a stable and repeatable psu testing setup.


    I highly recommend that industrial manufacturers be pointed out just like in xbit labs reviews. That way we will know that antec has 3 or more suppliers providing psu's and be able to tell the seasonics from the other crud ;)

  • Wesleyrpg - Thursday, July 12, 2007 - link

    hmm i wonder if thats why some people rave about Antec and some people like me curse them! I'd have to say Antec have the worst failure rate by far, probably at about 75% in the first year, where i can buy a $22 550W Generic (Honli) and only have about a 25% failure rate, maybe thats related to the power supplys released into australia by antec.
  • imaheadcase - Thursday, July 12, 2007 - link

    I kid! :P
  • gersson - Thursday, July 12, 2007 - link

    just a red 'X'
  • gersson - Thursday, July 12, 2007 - link

    nevermind -- working already :-)

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