Efficiency and Acoustics

One of the most important factors for an end-user in choosing a power supply is efficiency. Below we have three graphs that show the efficiency with 90, 120, and 230 VAC. The lower the input voltage is the lower the efficiency of the power supplies becomes; this is why the graphs on the last figure are much higher. We are calculating our loading chart according to Intel specifications of the latest ATX norm. However, we were asked to switch over to the 80Plus loading charts since more and more companies are using that now; rumors say that even Intel is using it already.

The difference between the specifications is that 80Plus is a more realistic calculation that loads the 12V rails much higher than the current Intel spec does. This results in higher efficiency ratings for starters. This is why our results don't quite match up with Enermax claims on their packaging; Enermax made that statement according to 80Plus tests.

At the lowest input voltage, the 625W Modu82+ performs very well with a very long period of high efficiency. The 385W performs the worst with a short summit of just 82% and 190W of load.

With 120VAC, the chart looks slightly different. Here we have the 525W version performing best and the power supply is able to come up with 84% at only 100W. It keeps this efficiency up to 400W and then slowly sinks. The small 385W version again performs worst and has only a short peak of 84% at 180W.

Finally, at 230VAC the graphs change again. As expected, the efficiency is much better. The 625W unit has a very nice and long lasting efficiency of over 85% from 100W of load. Even until full load of roughly 600W it keeps its efficiency high at a minimum of 82%. The 385W also performs well, but of course in a much smaller range. With only 50W of load, this power supply has 80% efficiency. It keeps efficiency above 82% even with 110% of load, which is a little more than 400W. These results clearly show the high performance of the tested units.

Acoustic Noise

The fan control unit is the same in all the units, and it regulates the fans according to the load of the power supply. All of the units stay totally silent with only 17dB(A) and 500 RPM until 50% of their load. The fan then starts turning faster and reaches 1500 RPM with maximum load applied to each unit. Only the 525W model doesn't quite reach 1500 RPM, topping out at 1300 RPM instead and thus creating less noise with only 24dB(A) with 110% load!

In general, these power supplies are simply not audible during normal use. The fans run at slightly less than 500 RPM, which is very slow. You can only hear the fan when you get your ear within an inch or two of the fan. You will then hear a sliding noise. Even at full load, 27dB(A) isn't very loud and will qualify as near-silent for most users. If you run a high-end graphics card or two, the fans on the GPUs will definitely drown out the noise of the power supply at any load.

DC Output Stability and Quality Conclusion and Prices


View All Comments

  • loslhotos - Tuesday, April 1, 2008 - link

    Maybe it's only my impression, but isn't the choke wire outside of the PCB hole?

  • Fuzzilla - Sunday, March 30, 2008 - link

    "...there are two main capacitors..."
    And who is the Mfgr of these for the Modu82+ series? Should I assume Hitachi as stated for the Pro82+ series?
    Are you sure there are three rails, what does the bottom of the main PCB look like? Photos please.
    According to your diagram the Modu82+ 525W has no floppy connector, Enermax specs state otherwise.
    "The solder joints in general aren't that great with Enermax,..."
    Really? Photos please.
    Regarding Detailed Voltage Distrubtion , Efficiency & Acoustic Comparison: What were the results for the Modu82+ 525W?
    Did OCP perform correctly?
    How was crossload performance?
    How did you test these PSU's?
  • jonp - Saturday, March 29, 2008 - link

    you guys need to get out into the real world and take a break if you have been anxiously awaiting, for months, the arrival of boxes that pump electrons. Reply
  • quanta - Wednesday, March 26, 2008 - link

    The article misses important pictures, including Voltage Distribution and efficiency graphs. Reply
  • Christoph Katzer - Thursday, March 27, 2008 - link

    So maybe you should read it more carefully... Reply
  • vajm1234 - Wednesday, March 26, 2008 - link

    hope u do that fast as i want all corsair 4nd 5 series psu to be there...especially that 450vx with other good psus Reply
  • feelingshorter - Wednesday, March 26, 2008 - link

    Due to marketing with higher and higher wattage PSU's, a lot of people still are clueless on how much a modern day system uses (or at least i am). So i was wondering of Anandtech can give typical systems in which would use said PSUs can be used safely and to maximize efficiency.

    Such as mention that a dual core, 9600GT system using the 385? Or a 8800GT + quad core using the higher ups? Or can a 385 watt PSU (being that its enermax) handle say a 8800GT + quad core? I remember many websites in the past stating that even well to do gaming system don't need as much watts as people would expect.
  • nilepez - Thursday, March 27, 2008 - link

    If the vast majority of power can be served on the 12V rails, then yes.

    an 8800GT less than 100W at full power. You can be fairly certain that the rest of your system pulls less than your graphics card (at least if it's core duo...havne't looked into quad cores).

    When you go to PSU calculators, those figures they recommend are based on everything in your system operating at 100%. maybe it's just me, but I've never had my GPU, CPU, HD and DVD all going at 100% at the same time. At idle, you're probably pulling under 100W with an 8800GT (512mb). If you're overclocking, it can vary.

    The main key is to get a good PSU, not necessarily a huge one, though I'm building one for my parents that's got a huge PSU (i've i'd seen this review 4 days ago, I would have bought the 385W enermax), because it was rated as very quiet....but these are apparently even quieter...and more efficient too.
  • Christoph Katzer - Wednesday, March 26, 2008 - link

    Correct and we are working on that kind of article already :) Reply
  • strafejumper - Tuesday, March 25, 2008 - link

    lot of places just focus on 800 and 1000 watt psu's

    i'm looking at the conclusion page and it says 350, 380, 385 !!!
    i don't upgrade everytime something new comes out so these power supplies are still very usable for me and im glad they get some attention.

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