Load Testing

For those of you that are curious as to some of the reasoning and equipment behind our PSU testing program here at TheFPSReview, we have put together an introduction for you. This program is based on what the author developed at [H]ardOCP and utilizes the equipment bequeathed to the author by Kyle Bennett. The testing we are conducting today is exactly as described in that document and start with our 120v, 100v, Torture, and 80 Plus Tests.

120v and 100v Load Testing Results

SilverStone NJ700 700W Fanless Power Supply 120v and 100v load testing results

Test #1 is equal to approximately 25% of the rated capacity of the SilverStone NJ700 at 45c. This makes Test #1 equal to 185W by loading the 12v rail to 13a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a. The results of Test #1 show the main positive DC output rails starting above nominal. The efficiency for this unit is starting off in excellent shape at a value of 91.08% at 120v AC input and 90.64% at 100v AC input. We see the housing temperature is 47C at 120v AC input and 49C at 100V AC input.

Test #2 is equal to approximately 50% of the rated capacity of the SilverStone NJ700 at 45c. This makes Test #2 equal to 327W by loading the 12v rail to 24a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.3a. Test #2 sees mixed results in the DC output voltages relative to what we saw with Test #1. The largest changes are up to a 0.02v increase on the 12v rail followed by a 0.01v drop on the 3.3v rail. The 5v rail, however, remained even with Test #1. The efficiency has moved up to 92.12% at 120v AC input and 91.61% at 100v AC input. We see a housing temperature of 48C at 120v AC input and 51C at 100V AC input.

Test #3 is equal to approximately 75% of the rated capacity of SilverStone NJ700 at 45c. This makes Test #3 equal to 502W by loading the 12v rail to 37a, the 5v rail to 5a, the 3.3v rail to 4a, the +5vsb to 2a, and the -12v to 0.3a. Test #3 mixed results in the DC output voltages relative to what we saw with Test #1. The largest changes are up to a 0.02v decrease on the 12v rail followed by a 0.01v drop on the 5v rail. The 3.3v rail, however, remained even with Test #2. The efficiency in Test #3 moves down to 92.04% at 120v AC input and up to 91.21% at 100v AC input. We see a housing temperature of 53C at 120v AC input and 56C at 100V AC input.

Test #4 is equal to approximately 100% of the rated capacity of the SilverStone NJ700 at 45c. This makes Test #4 equal to 702W by loading the 12v rail to 56a, the 5v rail to 1a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a. In the final regular test, we see the 12v rail move up by up to 0.02v. The minor rails, however, stay even with their Test #3 values. The efficiency has dropped as we see it come in at 91.23% at 120v AC input and 90.19% at 100v AC input. We see a housing temperature of 56C at 120v AC input and 61C at 100V AC input.

Torture Test

SilverStone NJ700 700W Fanless Power Supply torture test

The Torture Test is equal to approximately 80% of the rated capacity of the SilverStone NJ700 at 45C. This makes the Torture Test equal to 576W by loading the 12v rail to 42a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. At the end of the Torture Test, the NJ700 is still doing well. The DC output voltages are generally in line with what we have been seeing in the 120v load tests. The efficiency is excellent as we see a value of 91.74% and the housing temperature is 63C.

80 Plus Load Testing Results

SilverStone NJ700 700W Fanless Power Supply 80 plus load testing results

As we see here, the SilverStone NJ700 posts efficiency values of 90.34%-92.05%-90.51% efficient using 80 Plus’ load testing parameters. This puts the unit under the 80 Plus Titanium standard in the 25% and 50% tests by up to 1.95%. However, we do use different equipment than 80 Plus for our testing and there is always a bit of component variation.

Load Testing Summary

Much like the SilverStone NJ600 before it today, the SilverStone NJ700 did an excellent job in our initial load testing. When we look at the voltage regulation, we see that the NJ700 had peak changes of 0.04v on the 12v rail, 0.01v on the 5v rail, and 0.01v on the 3.3v rail. These absolute values are easily in the specification and simply awesome. In fact, they are better than all of the 700W units we have seen to date and may well be the best we see for quite some time!

When we look at the efficiency values posted today, we see that the NJ700 ranged from 91.08% to 92.12% efficient at 120v AC input and 90.19% to 91.61% efficient at 100v AC input. When we look at this units 80 Plus performance we see that it posted values of 90.34%-92.05%-90.51% which miss the 80 Plus Titanium standard by up to 1.95%! Lastly, the housing temperature peaked at 56C at 120v AC input, 61C at 100v AC input, and 63C during the Torture Test. With excellent starting results in today’s testing, let’s move on to the Transient Load Tests.

Paul Johnson

Paul is a long time PC hobbyist and tech enthusiast having gotten his start when he broke his first C64 quickly followed by breaking his first IBM XT. Most notably however, for 12 years, he served as the...

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14 Comments

  1. Good review. I think for me, once you mention Seasonic the rest is pretty well known. I hope they keep it up and other OEMs take note.
  2. WHATS OPP ON THIS? :ROFLMAO:


    Batman-Slapping-Robin-Meme-Explained.jpg

    I don’t want to have to get the load tester repaired any more than neccesary.

  3. haha I’m just busting chops.

    I gotcha. But, destructive testing of a power supply results in unexpected events. Each time I have to get the load tester repaired and recalibrated and certified it starts a $2k. So, not something I like to do.

  4. I gotcha. But, destructive testing of a power supply results in unexpected events. Each time I have to get the load tester repaired and recalibrated and certified it starts a $2k. So, not something I like to do.

    Well, in my opinion, OPP testing should not be destructive. Unless the PSU is malfunctioning or you just really wanted it to be and juiced it hard (like 480V 3p).

    Hitting a PSU with some overload, 125-150%, shouldn’t cause it to explode and should gracefully trigger OPP. Most of our industrial tests are to 150% of rated.

  5. Well, in my opinion, OPP testing should not be destructive. Unless the PSU is malfunctioning or you just really wanted it to be and juiced it hard (like 480V 3p).

    Hitting a PSU with some overload, 125-150%, shouldn’t cause it to explode and should gracefully trigger OPP. Most of our industrial tests are to 150% of rated.

    But, like I said before, there is not a spec. And without some sort of definition we have no idea where it is and where a catastrophic load will happen. So, until it is defined somewhere we can’t do a legitimate test for it.

  6. But, like I said before, there is not a spec. And without some sort of definition we have no idea where it is and where a catastrophic load will happen. So, until it is defined somewhere we can’t do a legitimate test for it.

    Ask the manufacturer, if they advertise the feature, it has a setpoint.

    That, or treat it like overclocking and just step it up slowly.

  7. Ask the manufacturer, if they advertise the feature, it has a setpoint.

    That, or treat it like overclocking and just step it up slowly.

    This is on the list of expensive things I’d like to see.

    Just note that they’re expensive, and as @Paul_Johnson notes above, prohibitively so.

    I’ll also say for the sake of perspective – while you want to know how a PSU behaves close to its limit, that’s your ‘reserve’. You’d usually want to leave say a 20% or more bit of ‘on paper’ headroom. Base your estimates on how hard you want to push the system and what components you expect, and add up the power draw, then leave some headroom above that.

    If you’re pushing a PSU close to its limit, you’ve made a.. miscalculation somewhere along the line :).

  8. Ask the manufacturer, if they advertise the feature, it has a setpoint.

    That, or treat it like overclocking and just step it up slowly.

    Well see, that is the problem. Most of the "manufacturers" are not manufacturers and don’t know (though SilverStone is not one of those that does not know). Also, I would have to have not just what they set it to but how they designed the protection. Then write a specific test for each and every unit that caters to their exact design. That means there would be no standardization to be able to compare units to. And without some sort of standardized definition we have no idea where a catastrophic load will happen. So, until it is defined somewhere we can’t do a legitimate test for it.

  9. What? You don’t like ground dwelling birds for your power supplies?

    Birds wouldn’t have been my first choice, but knowing that it is a bird name makes a lot more sense than some sort of jar one uses at night.

    My mind was drawn in the direction of chamber pots!

  10. My mind was drawn in the direction of chamber pots!

    Somehow – I blame Hunger Games – the name pattern sounded like a bird name. But like so many other names that are nominally English coming from countries where it isn’t a first language, I pretty much just accept stuff as it comes. I read plenty a pre-2000 motherboard manual too.

    So ‘chamber pot’ is fair game, IMO!

    On the other hand, with Gigabyte’s fiery ordeal still shaking out and questions on how such occurrences might be prevented, the ‘fanless’ nature of this Silverstone unit just now caught my eye.

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