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Enermax Digifanless 550W Power Supply Review

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Efficiency, Temperatures And Noise

Efficiency

Using the results from the previous page, we plotted a chart showing the efficiency of the EDF550AWN at low loads and at loads equal to 10 to 110 percent of the PSU's maximum-rated capacity.

The Enermax unit's efficiency is high. But the digital platform fails to impress us. Seasonic's analog platform, used by both Seasonic and SilverStone in their passively-cooled power supplies, performed much better, showing that analog components with the proper design can still be highly competitive, especially compared to early digital platforms. After all, this is the first digital PSU from Enermax. Hopefully, experience that the company gathers from its design phase will help improve future digital units. Analog designs are much more mature, since they have been around for many years and engineers know lots of ways to tweak their performance. Inevitably, it will take some time until we see digital PSUs that definitively surpass their analog counterparts.

Efficiency At Low Loads

In the next tests, we measure the EDF550AWN's efficiency at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dialed were 20, 40, 60 and 80W. This is important for representing when a PC is idle, with power-saving features turned on.

Test #12V5V3.3V5 VSBPower(DC/AC)EfficiencyPF/AC Volts
11.204A0.490A0.470A0.195A19.62W70.60%0.806
12.087V5.073V3.393V5.078V27.79W115.1V
22.439A0.978A0.972A0.390A39.70W81.34%0.898
12.082V5.071V3.390V5.069V48.81W115.0V
33.676A1.467A1.474A0.590A59.81W85.57%0.933
12.078V5.069V3.388V5.060V69.90W115.0V
44.903A1.973A1.947A0.790A79.78W87.66%0.952
12.074V5.068V3.386V5.050V91.01W115.0V

At light loads, the Enermax unit's efficiency is good. Even with a 20W load, it stays above 70 percent. The unit breaks the 80-percent mark in the second test with a 40W load, and in the next two tests, efficiency registers a nice boost. Without any doubt, this PSU is perfect for systems with low energy demands that spend long periods idle or with low utilization.

ZDPMS Efficiency Test Screenshots

Screenshots of the ZDPMS software below illustrate the four efficiency tests shown in the above table. The order of the screenshots is the same as the order of the tests.

The efficiency readings during the first and the third tests were accurate enough. However, in the other two tests, they were way off. Also, the voltage readings weren't as close to the real ones as measured on the connectors of the PSU using our equipment.

5VSB Efficiency

The ATX specification states that 5VSB standby supply efficiency should be as high as possible, recommending 50 percent or higher efficiency with 100mA of load, 60 percent or higher with 250mA of load and 70 percent or higher with 1A or more of load.

We take four measurements at 100, 250 and 1000mA, and one with the full load the 5VSB rail can handle. 

Test #5VSBPower (DC/AC)EfficiencyPF/AC Volts
10.101A0.51W72.86%0.062
5.083V0.70W115.1V
20.252A1.28W79.50%0.133
5.078V1.61W115.1V
31.002A5.06W81.88%0.275
5.051V6.18W115.2V
42.502A12.50W80.91%0.406
4.997V15.45W115.0V

With 115V input, the 5VSB rail is highly efficient. Enermax does a good job here.

Efficiency is significantly higher on the 5VSB rail with 115V input than it is with 230V. The Enermax unit performs well; however, the Seasonic platforms once more manage to take the lead.

Power Consumption In Idle And Standby

Mode12V5V3.3V5VSBPower (AC)PF/AC Volts
Idle12.085V5.086V3.397V5.085V6.93W0.372
115.1V
Standby0.08W0.007
115.3V

In the table above, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the PSU is in standby mode (without any load at 5VSB).

At standby, the PSU shows low energy levels, and it passes the ErP Lot 6 2013 requirements easily.

Delta Temperature And Output Noise

The following chart illustrates the delta between input and output temperature. The results were obtained at 38 to 45 degrees C ambient temperature.   

There is no cooling fan in this passive unit, so there is no noise output. We didn't notice any coil whine, either.

22 Comments Comment from the forums
  • blackmagnum 17 May 2015 11:00
    If you think buying a mid-range PSU that costs as much as an enthusiast gaming CPU or graphics card, then you have more money than sense.
    Reply
  • PaulBags 17 May 2015 11:35
    Why'd my commented get deleted? "This is a passively-cooled PSU, so you should install it with the top exhaust grille facing downward." is totally wrong advice, if you don't believe me read the warnings in the picture YOU took.
    Reply
  • Calculatron 17 May 2015 12:42
    Ironically, I have yet to try an Enermax PSU, although I really like their other products; I have an ETS-T40-TB, a whole myriad of their fans, and the Ostrog Pink case.
    Reply
  • uglyduckling81 17 May 2015 13:16
    "This is a passively-cooled PSU, so you should install it with the top exhaust grille facing downward. If you don’t follow this advice, hot air will be trapped inside the PSU"

    Hot air rises. If you have the opening facing down you will be trapping hot air inside. Read your own comment "top exhaust". 'Top' means on top, 'exhaust' means expulsion of air not intake.
    The PSU clearly has vents on the back and sides so I think it's a moot point either way but it's clearly a better idea to install it with the top opening facing upwards.
    Reply
  • nukemaster 17 May 2015 15:05
    15875927 said:
    Why'd my commented get deleted? "This is a passively-cooled PSU, so you should install it with the top exhaust grille facing downward." is totally wrong advice, if you don't believe me read the warnings in the picture YOU took.
    I think your post got lost(forum bug maybe), not removed. I would see if it was removed and it was not.

    I think this would depend on the case you are using to be honest.

    System air will cool it.

    If the power supply is at the top of your system putting its vent up will cause heat to have no place to go in many cases. Power supplies in the bottom of the case would be better served with the power supply vent face up.

    The power supply has software to let you see the temperatures anyway so you can test. Tom's tests in a hotbox so it is not an actual case.
    http://www.tomshardware.com/reviews/how-we-test-psu,4042.html
    Reply
  • Aris_Mp 17 May 2015 15:24
    guys sorry for this mistake. It is with the fan grill facing upwards and not down. This is how a single word can bring doom!
    Reply
  • Blueberries 17 May 2015 17:39
    These are solid! I'd take a SeaSonic SS-520FL2 for $140 over this any day, though!
    Reply
  • PaulBags 17 May 2015 20:00
    These are solid! I'd take a SeaSonic SS-520FL2 for $140 over this any day, though!
    I have the seasonic, I love it. I prefer the modular connector layout on it too, this emermax only offers a few oddly placed plugs by comparison. The cables arn't as good though, and you don't even get enough to populate all the plugs, although it's sufficent for most scenarios for a 520w PSU.

    I'd very much like to see AC cable clips become standard, I've had the ac work loose on me before when I turned a case slightly to plug something in, glad I didn't have anything important up at the time.


    To anyone who _would_ want the enermax over the seasonic I'm genuinely curious as to why. It's always good to learn and/or gain perspective.
    Reply
  • eklipz330 18 May 2015 03:52
    i just realized my 7 year warranty for my corsair hx750 expires this year QQ
    Reply
  • f-14 18 May 2015 03:52
    15875927 said:
    Why'd my commented get deleted? "This is a passively-cooled PSU, so you should install it with the top exhaust grille facing downward." is totally wrong advice, if you don't believe me read the warnings in the picture YOU took.
    I think your post got lost(forum bug maybe), not removed. I would see if it was removed and it was not.

    I think this would depend on the case you are using to be honest.

    System air will cool it.

    If the power supply is at the top of your system putting its vent up will cause heat to have no place to go in many cases. Power supplies in the bottom of the case would be better served with the power supply vent face up.

    The power supply has software to let you see the temperatures anyway so you can test. Tom's tests in a hotbox so it is not an actual case.
    http://www.tomshardware.com/reviews/how-we-test-psu,4042.html

    page 2 second set of pictures picture number 5 what does it specifically say? where does hotair go, where does cold air go, in a fanless case your argument is excellent advice on how to waste money and start a fire. if you are running an antec 1200 with all the fans unless this psu is mounted at the top with the vents down and all the other fans are set to intake into the case you are in great shape, however that mitigates the point of having a fanless psu, you go fanless because you don't want there to be any noise, much less a hoover vacuum for a case.

    i haven't read the warranty card, but i am sure it says something about keeping the psu vents facing up when mounted at the bottom of the case, when mounted on the side that would be interesting.

    nice psu, i will keep it in mind for the next time a customer wants a zero or low noise build.

    someday there will be a liquid cooled PSU, i laugh because of water conduction electricity, but where there is a will, there is a way to circumvent conductivity and deal with all that heat i am sure.
    Reply